This blog is about the intersection between evolutionary biology and food. But also about practical applications, sustainable agriculture, and general tasty things.
Every two years or so I notice a cyclical trend in the online “paleo” community. It’s the resurgence of dogmatic carnivory. It has two main themes: plants are “poisons” that cause most of our health problems and humans “evolved to be” very low carb. Always an undercurrent with some very zealous devotees (“The Bear” of Grateful Dead fame was probably one of its most prominent popularizers), it suddenly finds popularity among normally more moderate people, picking up some non-paleo low-carb followers in the process. Then it goes away again, hilariously with some of its top cheerleaders renouncing it in the process (like Danny Roddy).
It’s been back again lately. A few readers have written me about Anna who writes the blog Life Extension*. She is a graduate student in archaeology and social anthropology. Anna’s most popular post so far is “Debunking and Deconstructing Some ‘Myths of Paleo’. Part One: Tubers.” Sadly, an opportunity for greater communication to the public from a much-maligned discipline becomes a manifesto for low-carb diets. The tagline is “Glucose restriction represents not only the most crucial component of ancestral diets but is by far the easiest element to emulate.” I think we’ve heard this one before, but this time it is in language that is more authoritative than usual. This is the kind of writing I would have liked Paleofantasy to take on.
Unfortunately she doesn’t refer to sources directly in her text, so I’ve done my best to figure out which sources she is referring to.
Most archaeologists don’t go around promoting diets, because they recognize the limitations of their field. There is so much that is unknown and unknowable. It’s pretty easy for nearly anyone to pigeonhole what we do have to fit their own narratives.
The reduction in size and robusticity of the human skeleton is a clear temporal trend of newly agricultural communities. Diachronic skeletal comparisons reveal large-scale, significant reductions in growth rates.
Yes, of some newly agricultural communities, and that doesn't mean it stayed this way. I’ve written about it more than I would have liked. I just wrote about it in my last post about Paleofantasy (which cites this review).
Then a funny thing happened on the way from the preagricultural Mediterranean to the giant farms of today: people, at least some of them, got healthier, presumably as we adapted to the new way of life and food became more evenly distributed. The collection of skeletons from Egypt also shows that by 4,000 years ago, height had returned to its preagricultural levels, and only 20 percent of the population had telltale signs of poor nutrition in their teeth. Those trying to make the point that agriculture is bad for our bodies generally use skeletal material from immediately after the shift to farming as evidence, but a more long-term view is starting to tell a different story. - Marlena Zuk
It also brings up how questionably height is used in these narratives. The few hunter-gatherers that exist today are very very short (mostly due to genetics). The rest of the world has grown taller and taller. Staffan Lindeberg in his magnum opus suggests we are too tall from overnutrition. Other markers that extremists attempt to use to show that agricultural humans show a downward trend in terms of health suffer from similar limitations.
Instances of porotic hyperostosis brought on by iron deficiency anaemia increased dramatically in agricultural settings.
There is a new appreciation of the adaptability and flexibility of iron metabolism; as a result it has become apparent that diet plays a very minor role in the development of iron deficiency anemia. It is now understood that, rather than being detrimental, hypoferremia (deficiency of iron in the blood) is actually an adaptation to disease and microorganism invasion.”- Porotic hyperostosis: A new perspective
Either way, I’m not sure what the transition these communities in upheaval experienced has to do with whether or not tubers or any carbohydrates are bad for you. It wasn’t just the food that changed for these people, it was their entire way of life, and it was a transition that changed their biology. And while there are trends, there is no linear health decline. There is a more systematic database of human remains and health markers that is in the process of being created right now that should be a great resource in the future. At this point a lot of papers claiming a decline are using inappropriate sample sizes and statistical methods.
Far too little evolutionary time has passed for us to be successfully acclimated to the novel conditions of agricultural life.
Another common thread that is begging the question. How long is long enough? How many adaptations are enough?
Speaking of evolutionary time:
Spending most of our human history in glacial conditions, our physiology has consequently been modelled by the climatologic record, with only brief, temperate periods of reprieve that could conceivably allow any significant amount of edible plant life to have grown.
Like Nora Gedgauda's paleo book Primal Body, Primal Mind, which she cites for unknown reasons, this sentences implies to her lay readers than glacial conditions = something out of the movie Ice Age. Which is just not true. A glacial maximum left some people in the cold, but Africa was still quite warm, and if we are talking about evolutionary time, that’s where we spent most of it. Outside Africa, most humans seem to have clustered in fairly temperate refugia such as Southern Iberia during the last ice age.
Many think of the late Pleistocene as the “Ice Age”, a time when continental glaciers coveredmuch of the earth and where the land not under ice was inhabited by giant cold-adapted animals—wooly mammoth, wooly rhinoceros, and cave bears—pursued by hardy humanhunters. While this image may be somewhat accurate for part of the world, most of the earthremained unglaciated throughout the Pleistocene.” -In Glacial Environments Beyond Glacial Terrains: Human Eco-Dynamics in LatePleistocene Mediterranean Iberia
Of course “significant amount” is also going to be a point of contention. Only in the very coldest tip of the arctic do levels of plants in human diet fall to close to zero. Beyond that, many people might not be aware of levels of starch and sugar available in the environment because traditions surrounding them have died out. I have written quite a bit about Northern sources of carbohydrates- “Siberian potatoes” and Alaskan native plant foods.
Further information on the evolution of our diet can be garnered from the genetic data of present populations, which demonstrates the historically-late biological adaptation to less than minimal quantities of starch and to only few and specific starch compounds.
I assume this refers to amylyse (AMY1) copy number, the function and history of which is not quite clear, much like lactase persistence. For example, I do not possess lactase persistence, even though my ancestors probably raised livestock for dairy, they were diversified pastoralists, so it’s likely there was not enough selective pressure for them to develop this trait. They consumed dairy, but the majority of their diet was not dairy.
It is unlikely the ancestral human diet was as high in starch as some horticulturalist tropical diets are now, where the majority of calories come from starch. But in the end, the differences in AMY1 copy number between humans are small compared to our differences with other primates, indicating that perhaps this was selected for in our own evolution. And in the original paper it is kind of mind-boggling they use the Mbuti as a “low-starch” population given their high starch consumption.
The Mbuti are particularly interesting because they are hunter-gatherers, but trade their surplus meat for starch and have done this for quite some time (when this isn't available there are forest tubers utilized as fall-backs). The only time they don’t trade is when honey is in abundance.
Anna’s assertion that starch is comparatively “inefficient” compared to meat using optimal foraging models doesn’t mean that humans would have chosen to eat only or mostly meat. That data includes game from South American environments, which is unusually fatty in comparison to African game. Even in South America, such game is not available in unlimited amounts in the first place, which is why even hunter-gatherer cultures that have access to it like the Ache also extensively gather and process starch and gather honey.
The consequences of limited availability and time investment of edible Palaeolithic plant foods has been analysed by Stiner, who compared food class returns amongst contemporary hunter-gatherer groups. Stiner found the net energy yield of roots and tubers to range from 1,882 kj/hour to 6,120 kj/hour (not to mention the additional time needed to dedicate to preparation) compared to 63,398 kj/hour for large game.
Anna’s assertions stand in stark contrast to the paper she seems to cite:
Staple plant resources present an extreme contrast to large game animals with respect to prevailing economic currencies (Table 11.1). Large animals generally yield high returns per unit foraging time (kJ per hour) but are unpredictable resources. Seeds and nuts give much lower net yields per increment time (kJ per kilogram acquired), but they have potentially high yields with respect to the volume obtained and the area of land utilized.
Surveys of hunter-gatherers show overwhelmingly that preferred foods are fatty game and honey, highly caloric (and delicious), yet these are not the majority of the diet because they are not available in high predictable amounts, like the modern equivalents are.
As Kim Hill, who studies the Ache says “High-ranked items may be so rarely encounteredthat they represent only a very small proportion of the diet; low-ranked items in the optimalset may be encountered with sufficient frequency to contribute the bulk. It is interesting to note that on several occasions, reports of nearby palm fruit (ranked 12) were ignored, something that did not happen with oranges. On several other occasions people discussed the relative merits of hunting monkeys (ranked 11). reaching consensus that monkeys should not be pursued “because they are not fat.”
Anthropologists have theorized on the importance of having carbohydrate fallback foods in the event that high-fat game is not available, either because of seasonality or over-hunting. In these cases, “rabbit starvation” from excess protein is a real danger. Surviving off of game is a real challenge, which probably accounts for the fact that many humans have any exploited seemingly tedious to gather plant resources in nearly every environment.
Some of Anna’s arguments indicate that she has decided on some issues that are actually very controversial in anthropology and archaeology, such as the date of regular fire use (Anna asserts it was much later than many think) and that “However, plants have been preserved in the Lower Palaeolithic, and they are used primarily for functional and material – rather than nutritional – purposes.”
She does admit that “I will concede however that absence of evidence is not evidence of absence” but then goes on to list some sites that show possible non-food-related plant use that aren’t even associated with Homo sapiens, many are hominid offshoots that are unlikely to have contributed to our line (except for some of us who have a possible small amount of neanderthal ancestry). Other sites she mentions aren’t dated to the lower Paleolithic anyway.
Later sites such as Kebara she also dismisses, implying that legumes would have been used as fire starters rather than food. But admits that hominids would have supplemented their diet with “low glycemic” foods when meat was scarce.
Firstly, Neanderthals were highly carnivorous and physiologically inept at digesting plant foods. This can be measured using the megadontia quotient of Neanderthal postcanine tooth area in relation to body mass, which reveals that H. neanderthalensis must have consumed a greater than 80% animal diet. Nonetheless, the evidence of phytoliths and grains from Neanderthal skeletons at Shanidar Cave may reveal the rare consumption of starches in this singular context, but not the deleterious costs to the health of those that ate them.
The megadontia quotient, which is controversial in the first place, is not meant to be used in this way. Neither is the also mentioned expensive tissue hypothesis. They are meant to analyze use of uncooked fibrous plant foods and is not particularly enlightening in the case of large-brained hominids with cultural adaptations to food such as cooking. Some of the most recent research that reappraises the carnivorous theory of neanderthals is covered in this recent talk by neanderthal experts Dr. Margaret J. Schoeninger and Dr. Alison S. Brooks.
Humans show up as carnivores, even when they are known corn-eating agriuculturalists, like these people. But what happens when you plot other plants?
Now the data makes more sense (remember this data is showing where protein in the diet came from, it doesn't tell us how much protein was eaten).
As you can see, initial isotopic studies (which can only show where the protein came from, not the amount of protein in the diet) that showed neantherthals as top carnivores came into question when farming populations were showing similar values. They realized that they needed to consider analyzing plants based on their most nutritious fractions, since when was the last time anyone sane ate something like a whole stalk of corn, husk and all? Another great paper by John D. Speth also summarizes some of the recent research on neanderthal diets and debunks hypercarnivory.
humans were no longer able to transmute fibre into fat – as other primates can (consequently, they eat a high-fat diet) – through fermentation in the large intestine.
This, as anthropologist Dr. Richard Wrangham has pointed out, could also be an adaptation to cooking. And we didn’t lose this ability, it is just reduced, though no biologist would argue it the SCFA produced in the colon, which can provide calories and also modulate inflammation, are unimportant. SCFA metabolism is not comparable to longer chain fatty acid metabolism, so it’s not really appropriate to call these diets “high fat.” Furthermore, there are other primates with similar guts to ours like capuchins, who most certainly do not eat a carnivorous diet– they eat sugary fruit. But it’s very hard to compare our guts to the guts of other animals since cultural traits like cooking are so important for our food consumption.
I think it’s a bit amusing to read these posts alongside those of PaleoVeganology, written by a graduate student in paleontology who criticizes many popular paleo narratives. However much I disagree with him on the issue of modern diet choices, I commend him for not using his expertise to promote his chosen diet- he is explicit that his dietary choices are built on modern ethics and not the murky past.
The skeletons at Shanidar are certainly the first of many analyses of starches on teeth, which rules out theories like that plants were only used as decorations or fire starters. Since that first paper was published, others using the same method have followed and more will. But there is no way to use such data to speculate on how often or how much of these foods were consumed.
The coprolite “paper” that Nora Gedgaudas frequently cites also comes up, which I’ve addressed here.
Another common thread in carnivore narratives is that plants were used “only” as medicinals. I would not consider this as insignificant in any way– in most cultures, the line between food and medicine is a thin one. Many foods we enjoy as foods these days have medicinal roots.
Anna rightly criticizes the use of non-hunter-gatherers as hunter-gatherer proxies in writings about the so-called paleo diet and then cites a study that does the exact same thing-
In an attempt to reconstruct the diet of ice age hominids, a recent study analysed the macronutrient dietary composition of existing hunter-gatherer groups within latitude intervals from 41° to greater than 60°.
But where did this data come from? Anthropologist Katherine Milton responded quite well to this paper by Cordain:
The hunter-gatherer data used by Cordain et al (4) came from the Ethnographic Atlas (5), a cross-cultural index compiled largely from 20th century sources and written by ethnographers or others with disparate backgrounds, rarely interested in diet per se or trained in dietary collection techniques. By the 20th century, most hunter-gatherers had vanished; many of those who remained had been displaced to marginal environments. Some societies coded as hunter-gatherers in the Atlas probably were not exclusively hunter-gatherers or were displaced agricultural peoples. Because most of the ethnographers were male, they often did not associate with women, who typically collect and process plant resources.- Katherine Milton
The Ethnographic Atlas used in the “study” is available online and quite clearly does not contain 229 pure hunter-gatherer cultures. The 229 Cordain uses includes people who trade for or cultivate foods.
There is no evidence that mostly carnivorous groups of humans have particularly high longevity and in fact mummies, whatever their limits, have shown people eating these diets were not in fantastic condition, which of course like the bad condition of some early agriculturalists cannot be blamed on their diet.
It is awfully convenient to build a narrative to convince people to eat a limited diet based on the murky unknowns of the far past and near-mythical groups of supposedly extremely healthy carnivorous hominids. The carnivore-ape hypothesis is about as credible as the aquatic ape one.
One of the problems with human evolution, as opposed to, say, rocket science, is that everybody feels that their opinion has value irrespective of their prior knowledge (the outraged academic in the encounter above was a scientist, but not a biologist, still less an evolutionary biologist). The reason is obvious – we are all human beings, so we think we know all about it, intuitively. What we think about human evolution "stands to reason". Hardly a month goes by without my receiving, at my desk at Nature, an exegesis on the reasons how or why human beings evolved to be this way or that. They are always nonsense, and for the same reason. They find some quirk of anatomy, extrapolate that into a grand scheme, and then cherry-pick attributes that seem to fit that scheme, ignoring any contrary evidence. Adherence to such schemes become matters of belief, not evidence. That's not science – that's creationism.
I saw the same story building among vegans, who often craft similar narratives around our lineage's long plant-eating past. It speaks for a deep desire for people to justify their own choices. What all these dietary narratives have in common is that they confirm a particular limited diet is our “natural” diet and one that is best for humans, animals, and the environment. It’s not possible for them all to be right, and that’s because none of them are.
Ancient humans ate a large variety of foods, which is why we are adapted to so many. Human variation is high though, since our lineage has become so populous and geographically wide-ranging. There are many reasons for a modern human to adopt a low-carbohydrate or limited carbohydrate diet either temporarily or permanently. None of those have to do with this being the optimal diet for all humans or with a mostly-carnivorous ancestry.
I guess I’m kind of late to the party on reviewing this book, but I actually haven’t noticed a lot of reviews of it, which is surprising given the amount of buzz the articles about it generated. I also suspect some reviewers didn’t actually read it, since they seemed abnormally fixated on defending their paleo diet, when the book only has two out of ten chapters devoted solely to diet and covers many other topics.
Like Marlene Zuk, I am also quite critical of some of the movements that use (and mis-use) evolutionary logic like the paleo diet. So I wanted to like this book.
It has its good moments, but is overall in need of a good editor. It could be much shorter. And much less meandering.
Much of the skepticism is directly towards the frequently-inane postings on online discussion boards, which I a have the misfortune of being very familiar with having moderated one of the most popular until I rage-quit in annoyance.
While a lot of people get dumb advice on internet discussion boards, do they really define these movements? While they are fun strawmen to take down easily, most people don’t take such posts seriously. What they take seriously is the often scientific-sounding books written by various gurus, often with many letters, legitimate and not, preceding and following their names. While she mentions them, it’s only in passing. Her “paleofantasy” seems to consist mainly of cacophony of crowd-sourced internet discussion.
Not to say you won’t learn anything from this book, but it hardly challenges the status quo, which makes the hysteric reactions of many against it and the author seem all the more ridiculous. A lot of it reminds me of the excellent The Beak of The Finch or The 10,000 Year Explosion. She covers many methods that evolutionary biologists use to understand evolution, why they matter, and common misconceptions about them.
But if only people were talking about evolution when they were talking about the paleo diet. Talk about actual evolutionary biology and you might be met by some of the silent crickets that Zuk studies. Only 54% of paleo dieters in a recent survey accept evolution as a fact.
But it’s beyond that the increasing specialization in of academia becomes a limitation. Zuk specializes in the evolution of crickets, which yes, does have surprisingly broad applicability, but she spends a long time on that and other similar research that I think a skeptic would find irrelevant and unconvincing. I read The Beak of the Finch, which discusses this type of research in length, in high school, and it didn't stop me from adopting the paleo diet narrative. I think the most common problems with the “paleo” worldview come from anthropology. For example, misinterpretations of isotopic studies, coprolite fossils, and paleopathological surveys are used very often to justify “paleo” diets.
On the cultural anthropology side of things, people often seem very confused by terms like “hunter-gatherer” or “forager.” Rather than elucidating the complexity of historical humans lifestyles, the book muddles this further in parts. If you were confused about this before, you’ll stay confused, and a clarification would improve her arguments anyway. For example, whether or not the Yanomani (of the Chagnon controversy) are relevant to revealing some aspect of hunter-gatherer “human nature” is pretty questionable considering that while they do forage and hunt for some of their food, they are horticulturalists, a lifestyle that probably not much older than agriculture. Same goes for Jared Diamonds extrapolations from the horticulturalists of Papua New Guinea in The World Before Yesterday.
This is also common in Paleo diet books– authors like Cordain cite starch-cultivating horticulturalists like The Kitavans when convenient, while recommending a diet that bears little resemblance to theirs. I noticed recently that paleo guru Art De Vany’s blog header has a picture of some imposingly muscular tribal warriors. The site doesn’t seem to say anything about them, but I knew they are Asaro “mudmen” of Papua New Guinea, who are horticulturalists and grow many crops that De Vany would view as unhealthy. It is a shame to see them exploited to promote his diet and as of late, extensive advertising of his own supplements.
Fuled by sweet potatoes, sugary fruit, and peanuts they grew in their forest gardens
If you are confused, for almost all of the paleolithic humans were nomadic hunter-gatherers with primitive weapons. There are really no people today who practice this lifestyle. If agriculture is a drop in the bucket of human history from a relative perspective, even the innovations of the Middle and Upper Paleolithic, are similar in relative timescale. These innovations included better weapons- the atlatl and later the bow and arrow, which would have affected hunting significantly. They also included the culinarily important pottery and grease-processing (smashing up bones to make a fat and protein rich broth). I made this crappy timeline that gives a vague idea of some of these innovations in human history. What time do you choose as the optimum?
Our ancestors’ diets clearly changed dramatically and repeatedly over the last tens, not to mention hundreds, of thousands of years, even before the advent of agriculture.
Even the few representatives of nomadic hunter-gatherers that exist on the planet use these relatively modern technologies, like the Hadza’s bows.
I don’t think these groups of people are irrelevant to health discussions though, if anything, these people show that diversity of lifeways in which our species has been able to thrive, a thread that seems constant no matter the time. And every lifeway has involved trade-offs. For example, while rheumatoid arthritis, which is common in industrialized first world cultures these days, seems to have been rare in foraging cultures, osteoarthritis seems to have been more common.
And in the end while it’s fascinating to think about how so much we are familiar with is “new” in their scale of geologic time, Zuk rightly points that evolution works faster than many might imagine.
I think the sections on lactase tolerance, which talk about in how many places and ways humans acquired this trait, are fascinating. But left also many unanswered questions that show just how far we have to go to understanding human evolution.
Interestingly, about half of the Hadza people of Tanzania were found to have the lactase persistence gene—a hefty proportion, given that they are hunter-gatherers, not herders. Why did the Hadza evolve a trait they don’t use? Tishkoff and coworkers speculate that the gene might be useful in a different context. The same enzyme that enables the splitting of the lactose molecule is also used to break down phlorizin, a bitter compound in some of the native plants of Tanzania. Could the lactase persistence gene also help with digestion of other substances? No one knows for sure, but the idea certainly bears further investigation.
But while she mentions a little elephant in the room, which is our microbiota. Of “our” cells, bacterial cells outnumber “human” cells ten to one. And they have had a lot more generations to evolve than “we” have.
Microbiologist Jeffrey Gordon says, “The gut microbial community can be viewed as a metabolic organ—an organ within an organ . . . It’s like bringing a set of utensils to a dinner party that the host does not have.” 44 As our diets change, so does our internal menagerie, which in turn allows us to eat more and different kinds of foods. The caveman wouldn’t just find our modern cuisine foreign; the microbes inside of us, were he able to see them, would be at least as strange.
I like that she takes on the common narrative of “people were really healthy until they became farmers and then they shrunk and had bad teeth etc.” The reality is while some of the earliest agrarian cultures did seem to suffer compared to their predecessors, it wasn’t all about the food and people by and large recovered. Besides, if we were going to pick diets based on bone and teeth health, we might as well pick the pastoralists like Masaai, who tend to be much much much taller than any hunter-gatherers.
Then a funny thing happened on the way from the preagricultural Mediterranean to the giant farms of today: people, at least some of them, got healthier, presumably as we adapted to the new way of life and food became more evenly distributed. The collection of skeletons from Egypt also shows that by 4,000 years ago, height had returned to its preagricultural levels, and only 20 percent of the population had telltale signs of poor nutrition in their teeth. Those trying to make the point that agriculture is bad for our bodies generally use skeletal material from immediately after the shift to farming as evidence, but a more long-term view is starting to tell a different story.
Many paleo diet books present our species as that of fragile creatures rather than what we really are, which is the consummate omnivore resilient and adaptable enough to thrive on a large range of foods. A curious being, that was travelled far and wide and tasted many things, rather than being defined by fear and a narrow food exceptionalism. I’ve even seen people, some of them fairly well-known bloggers, on Twitter and Facebook discussing buying an island where “paleo dieters” could be free from “non-foods” like grains and the people that eat them. It’s not as bad as blog posts from paleo dieters travelling in foreign countries who talk about how difficult it is to explain their special food to the local people. Traditional cultures are venerated, maybe even exploited, unless they don’t fit the paleo narrative.
The question is whether the various forms of the paleo diet really do replicate what our ancestors ate.
Unfortunately Paleofantasy focuses on this absurd strawman of dietary replication and only begins to scratch the surface of neurotic botany of many paleo writings. Books that fret about whether or not “nightshades” grew in Paleolithic Savanna Africa and their plant chemicals, while blithely consuming other classes of similarly alien plants with other potentially problematic chemicals. Because that’s what plants are– bundles of chemicals that can be friend or foe depending on amounts and contexts.
The skeptics she cites aren’t much better than the internet commenters representing paleo. They include the Ethnographic Atlas, a survey of modern populations, that she claims puts to “rest the notion of our carnivorous ancestors.” Or the U.S. News & World Report’s rating of diets.
It doesn’t take an evolutionary biologist to understand what the paleo diet has become, especially in alliance with the low-carb diet promoters, industrial supplement companies, or the standard dieting-culture food fear mongerers. It functions not as an attempt to use evolutionary biology to understand the human diet, but has become a social engineering scam to sell mediocre books, processed powders, and other crap. It was only about evolution in the beginning, mostly it’s just a diet in caveman clothing now.
Paleofantasy has just come along for the ride. It’s not going to convince very many people caught in the scam. It’s just going to make those who haven’t feel smug. At least it might teach a few people about evolutionary biology.
And I liked the section about attachment parenting, which is surprisingly rational about the matter, a welcome break from so many writings that either are almost religious about it or decry it as some kind of upper middle class fad.
The evolutionary psychology section is also not as critical as I thought it would be from the reactions of those are are enamoured with the subject.
There is a long section on barefoot running, which talks about how some paleo diet proponents like Art De Vany think we did not evolve for long-distance running and other evolutionary fitness advocates like anthropologist Dan Lieberman think is it a critical part of our evolutionary heritage. I think this highlights the fact that the past is so hazy that it’s pretty easy to use it to support a whole host of contradictory arguments.
It’s a shame Zuk tilted at internet idiot windmills and not at the far more sophisticated arguments that are dressed up as science. I sometimes wonder if publishing companies don’t want authors to criticize other authors. They have 199 Paleo Fried Chicken Recipes (I made that up, but it’s not that far out) and other book-like products to push before people get bored.
These books are also relentlessly shallow shadows of some of the earliest texts in the genre of using the deep past to better understand how we should live. Recently I was struck by the similarity in the cover of The Primal Connection: Follow Your Genetic Blueprint to Health and Happiness and the late Paul Shepard’s Coming Home to the Pleistocene.
I read Coming Home to the Pleistocene when I was twenty. While I certainly don’t agree with everything in it, it is beautifully-written and thought-provoking. It challenged the way I thought about the world. Paul was not afraid to espouse controversial ideas, unlike the books from the diet industry that turn the original ideas into drivelling Flintstones platitudes in order to appeal to everyone. I suspect people will still be reading Shepard in a decade when all the paleo publishing bubble books languish in the bargain bin.
Zuk says in closing that “I am all for examining human health and behavior in an evolutionary context, and part of that context requires understanding the environment in which we evolved.” I agree with this. I think evolution is important and will continue to improve our understanding of our world. And I eagerly await a book that more fervently challenges common misconceptions about it.
I occasionally get emails and tweets admonishing me for being hostile to paleo and low-carb, having moved on and having to take a glancing blow behind me. It’s not an unfamiliar experience– I received the same when I stopped being vegan.
The truth is that I’m not hostile to paleo, low-carb, or vegan. All three represent food subcultures that taught me a lot about food and how it affects my health. I am thankful for that. Unfortunately all have quasi-religious underpinnings that can be detrimental to health. They are also hostile to critics.
It has been very difficult for me as a skeptic since criticism is frequently deemed to be a personal attack and is ironically often answered with personal attacks. Furthermore, when I was embedded with it socially, it was almost if you spoke up, you were in danger of being socially ostracized. It is my own experience that no one is blacklisted even for the worst behavior...unless they are openly skeptical.
It has been hard to leave. I mean there were good things– I got involved with grass-fed livestock because of it and many of my best customers, friends, and mentors also have a similar story. I thought maybe things could go back to the way they were when I started, when it was far more casual on a dietary level and it was largely a movement of people passionate about things like sustainable food, anthropology, evolutionary biology, and figuring out what worked for them.
I have told my own health story what seems like a thousand times, but the thing is I got better without being very restrictive at all beyond a period of very low carbing that had a targeted purpose, which was to allow my stomach to heal. It was more about adding foods to my diet such as meat and seafood then subtracting them, as well as letting go of dietary dogmas that were damaging my health like the idea that the best way to treat stomach issues was with more fiber or that fat was bad. It was also about diversifying the sources of food and the foods I relied on. I was only about 80% paleo then. It was fun and interesting to be a part of. I never worried about some ice cream or beer.
In Sweden I was very healthy until towards the end of my stay, when I think I messed up my stomach with NSAIDs again. I took to the corners of the internet where I found fringe diets for messed up people like the Specific Carbohydrate Diet, VLC (very low carb), raw paleo, and the Failsafe diet. I learned from these, though I never adopted them fully. In some ways they were bad because they foster extreme nitpicking, including lots of combing through papers, finding out of context studies to make people paranoid about food. In other ways they were good, because they helped me realize that there were more targeted approaches to my issues rather than just thinking about what I did or did not probably “evolve to eat.”
When I moved to New York City from Sweden I had trouble adjusting. I met most of the people I hung out with through Paleo meetups. At the time I think the larger community was moving towards those fringe diets I had encountered becoming more what paleo was about. Paleo was adopting the food paranoia of the aforementioned fringe diets combined with the hubris of the idea that it was the optimal human diet our ancestors were supposedly so healthy on. It crossed the line from awareness to fear-mongering, with more and more leaders associated with it promoting the idea that even if you feel good, you are being quietly “damaged” by certain demonized foods. Much to my chagrin as someone who is very interested in evolution, I noticed the movement was minimizing the role evolution played. Around this time I was first called an “elitist” for pointing out a major figure in the movement rejected that evolution even existed.
At the same time it was increasingly hard for me to accept that this dietary philosophy was the optimal solution. My testimonial was true– I did feel better, but better than what? Things were up and down. Episodes of fatigue haunted me, as well as my stomach problems returning intermittently. My response was to turn to the internet, where I became increasingly convinced that certain “bad” foods I was eating occasionally like beer were the culprit. I had to be better at this diet, so I gave them up. I didn’t feel any better. I met a lot of people in real life who had glowing online testimonials, but who were obviously struggling as well. I felt disillusioned.
The composition of people who mattered was also changing from quasi-anarchist back to the land hippy types to more and more slick marketing people who seemed to have little interest in anything beyond selling products, wearing leopard print, and eating bacon. The first processed "paleo" “products” appeared on the market. But at that point I was in too deep. Almost all my friends were from paleo. I wanted to save it from its growing association with stock internet junk science that I had once seen pollute the vegan community.
Also the movement was getting an infusion from some new blood, some input from the Weston A. Price Crowd for example from Chris Masterjohn, and Paul Jaminet’s Perfect Health Diet made people suddenly less afraid of things like rice. Influced by them and NEEDING to make a change very much after my serious fainting episode, I started eating white rice regularly again, as well as more carbs in general. I felt a lot better, but still continued to have health problems, particularly with my energy levels.
The paleo community however was just getting worse. It started looking more like a front to sell crap and a bunch of low-quality content farms rather than a community centered around real food. I started speaking out about it and experienced large amounts of harassment and then when I complained about that I was basically told to shut up and that I was attacking people who had devoted their lives to saving people (sounded pretty familiar to me from veganism). Behind the scenes, many of the figures I had admired were not what they seemed. The discourse had gone toxic.
But I was really really fortunate offline. I moved to Chicago. I waffled about being paleo-ish for a time, trying to get back to that original spirit I had about it in the beginning. I told myself I’d just remain gluten-free and “mostly paleo.” I had learned about FODMAPs and adopted that procol with good results getting my stomach stable. But then I joined Crossfit and completely lacked the energy to do much of anything. I crashed again.
Luckily I went on a trip to Europe. I ate what I wanted and felt great. After that I was pretty much done with paleo, even as paleo-ish or 80% paleo like I was before, though I remain interested in learning from physical anthropology and evolutionary biology, that’s pretty far from what paleo is about these days anyway and when it is it’s a bowdlerized scientifically anemic version. I turned down a book deal, knowing I was not qualified to write a book yet and that paleo community-associated publishers were churning out consistently low-quality books with little critical editing. I was ready to try new things.
Online, I started hanging out with the “bad kids”- the ex paleos, which is its own little movement at this point. It was probably started by Matt Stone who has been variously mocked all over the paleo community despite probably being able to make a good entry into the vapid testimonial wars the various gurus engage in. From Danny Roddy I started exploring Ray Peat’s work, though I don’t completely embrace it 100%, it gave me the courage to eat the ice cream I once enjoyed with impunity, as well as things like orange juice, which pretty much banished the fatigue episodes. I also realized via Amber of Go Kaleo that I needed to just stop trying to have a diet and “Eat the Food,” that all these years I’d been trapped in an unconscious haze of chronic undernutrition calorically. I never meant to eat too little, but so much of appetite is unconscious.
My appetite was frequently suppressed to the point of nonexistence, which was compounded by fear of eating certain foods like grains, so having to make a huge effort to eat a meal. Some people I’ve met seem to be able to get out of it while maintaining a particular diet, particularly if they monitor themselves very carefully, but I wasn’t able to and I think it’s the same for many people. Maybe our hunger signals can be broken both ways, not just in the overeating direction our culture is more worried about. In the end I realized I was doing this out of fear, because of food paranoia, not because it was the best way for me to fuel myself.
Since then a lot of my intolerances have gone away. It could have just been improving my metabolism through ending the chronic undereating or the probiotic supplementation I decided to pursue more aggressively. I stopped taking all supplements except for the Pearls IC, which I make sure to take every single day, and bromelain. I drink milk (despite being genetically lactose intolerant) and eat things like rye, broccoli, cauliflower, and other foods that used to tie my stomach in knots. I think the difference is I am aware that most intolerances are dose-dependent and potentially modifiable (barring a serious autoimmune disorder like celiac), not a limitation of evolution.
I think taking some of the approaches paleo has borrowed from or skimmed off (FODMAPs for digestive issues, very low carb temporarily for heartburn, ketogenic for certain neurological issues, awareness of gluten intolerance and sensitivity) and applying them in a targeted manner would be much more effective without the baggage. A lot of times I see people doing a strict paleo challenge who really could benefit from an elimination diet. Yes, some of the approaches have a re-trial phase after the challenge, but considering what we know about gut bacteria and digestion that is not the best approach. When you don't eat a food, your body will sometimes downregulate enzymes used to digest it and your gut bacterial population will shift. Vegans sometimes have issues re-introducing meat because the production of certain protein-digested enzymes is downregulated. Does that mean meat is bad? No, it means it needs to be reintroduced gradually and carefully.
I also can't deny that there were family members and friends who adopted paleo because of me, as well certain people I met through paleo that I grew close with who I saw really struggle with health issues, caught in the same trap I was. Some of them are doing better now, some of them aren't. I feel just as bad about a few of them as I feel about a friend from my past who I introduced to veganism and who now has terrible health problems and won't even consider there might be something beyond veganism that would help. These people are my anti-testimonials, especially since so many of them post online about their success on the paleo diet while I see them crashing.
Offline, my social life changed as well. I met people who really loved food, all kinds of food, and I’m grateful for them every day. I don’t have a diet anymore. I largely eat what I want, but thankfully what I want is largely from-scratch food made with local plants, pastured animal products, and wild seafood. In some ways my diet is more "paleolithic" in spirit than ever, considering its anti-fragile diversity of plants and animals, including many wild foods.
So I’ll continue to write here about evolutionary nutrition. And point out resources from the paleo community if I feel they are useful and good, as well as continuing skeptic writing about certain paleo topics. But I do not consider myself a paleo dieter, writer, or anything like that. My choice to distance myself is because I do not like the way the community treats skeptics or people who do not do well while paleo. In these ways it is nearly identical to the vegan community it frequently derides. It is sad, but not at all surprising, to see some gurus and bloggers finally come out as feeling not so great. The community’s response seems to usually be to increase fat in the diet or restrict it further. Or to embrace diagnoses that are unknown to the scientific literature (parasites a normal doctor can’t detect but a special “practitioner” can, adrenal fatigue which is usually self diagnosed or diagnosed questionably*) to explain things that are often simply undernutrition. Leave and you simply “didn’t do the diet right,” a convenient way to dismiss problems. It's too bad to see it go this way, but seems to be the way many internet diet communities end up.
When people ask me about paleo these days, I recommend they explore it, but also explore a lot of other food books with a skeptical mind. And to explore less sexy solutions like FODMAPs. And ultimately to consider not adopting a "diet" at all, but a greater awareness and a better relationship with the food system. Like ex-low-carber Darya Pino, I emphasize unprocessed foods from healthy food systems. The farmer's market, the pasture, the woodlands are my solace.
And yeah, I'm enjoying some chilaquiles made with local corn tortillas and a good beer while writing this, and no, my biomarkers haven't changed in the past year except my HDL is a lot higher. And I'm loving food rather than fearing it.
*I was tested for adrenal insufficiency by an endocrinologist when I fainted, which is advised if you suspect adrenal issues
Edit: I honestly can't believe that people are commenting that I'm actually still paleo but with some cheats. C'mon people. I'm eating sandwiches. I bake BREAD with GLUTEN in it. I drink liquid sugar. And other people are commenting that meat is the best food ever and why would anyone eat grains which are inferior. I never understood that argument. Just because a food is more nutritious doesn't mean it should be the only food you eat. Most foraging peoples get their calories from a bland not very nutritious source and fill int he blanks with a variety of plants and animals.
I've seen the idea that there are no primates adapted to eating grains, but actually there is a primate that is better adapted to such a diet than any others. It's the gelada (Theropithecus gelada), which lives only in the Ethopian highland grasslands. The gelada is the only living member of genus the Theropithecus. Several larger gelada species once roamed most of Africa, including the terrifying giant gelada, which was around the size of a modern gorilla. But now there is just one, which is also one of the few primates that endures sub-freezing temperatures, which occur at night in the highlands.
The gelada is also quite interesting because it is a grazer, relying mainly on grass. It prefers the seeds of the grass, which are yes, grains.
This is unusual for primates. Some, like anthropologist Clifford Jolly, have speculated that hominids once occupied a similar niche. But this was mostly in the 1970s and this model for understanding human origins has fallen out of favor. Some extinct lines on the family tree (Paranthropus for example) were thought to have eaten similar diets based on low-quality plants, but more recent evidence has cast doubt on this theory. Frederick Szalay's reply to Jolly's paper in 1975 noted that as climate changed, hominids and the ancestors of gelada may have both moved into the grasslands.
But as hominids rose, the Theropithecus genus fell, backed into a corner by adapatations to eating grass that seem incomplete and inefficient. Geladas require very high quality grass, not the low quality grass that started to dominate as Africa warmed up again.
The gelada and related baboon line seems to have a longer history of consuming starchier foods than the frugivorous lines that led to us. One piece of evidence is that baboons and geladas have higher salivary amylase expression than even humans cultures adapted to high starch diets.
Unfortunately, it seems that particular this genus adapted itself into a corner, with adaptations not good enough to compete with animals like zebras for the increasingly low-quality grasses in the warmer low-altitude grasslands, but complete enough that grass-eating was probably obligatory. Primates with an ability to consume a more flexible diet, like our ancestors, rose, while most Theropithecus died out.
Why such big scary teeth on a grass eater? Big scary teeth are about more than food, they are also the hallmark of territorial species where males fight for domination of harems of females as seen in this video of a gelada male battle.
While geladas were busy chomping on grass pretty much all day, there is some good evidence our ancestors were scavenging large animal carcasses, developing a taste for meat and perhaps spurring us to eventually hunt and develop tools to acquire more protein this way. The geladas went the route of low-quality protein, while the hominids went the route of high-quality protein, protein that may have allowed us to develop large brains and free up time from foraging to develop advanced culture. Geladas probably got less intelligent due to their overspecialization, while hominids and their closely related baboon cousins used their intelligence and flexibility to thrive in a variety of habitats.
Later, our niches would cross again as humans developed our own way to extract energy more efficiently from grass through technology and selective breeding for grain yields. Not surprisingly, geladas are thrilled to munch on such high quality grasses. While they are not a big as their ancestors, they are still a formidable pest ,as this Human Planet video shows:
Researching geladas might give us valuable clues to understanding our own species. For example, looking at the adaptations geladas have to eating their diet could tell us something about the kind of challenges a grain-eating primate faces and we could compare them to our own physiology to see how well we have adapted or not adapted to similar dietary challenges. However, geladas eat wild uncooked grasses, whereas humans have an entire culture of complex preparation that alters the structure and composition of our food significantly through grinding, fermenting, cooking, and other technology.
I want to explore the evolution of the evolutionary nutrition concept and how evolution was lost from it.
An early variant, The Stone Age Diet, by Walter L. Voegtlin, shows up in the record in 1975, but whether this carnivorous book is an ancestor of later variants is questionable, so it's hard to consider it an ancestor. A more likely candidate would be the paper written in 1985 by Dr. Boyd Eaton and Dr. Melvin Konner, Paleolithic nutrition. A consideration of its nature and current implications. While elements of the paper seem dated today, it was a pioneering collaboration between a medical doctor and a medical anthropologist.
This paper explored how evolutionary concepts could shed light on modern health problems. It was not just a paper about eating well, it was about eating well in the context of human beings having a long evolutionary history, one shared by many other species. And that the selection pressures faced during the long evolution of primitive species to humans could tell us things about diseases, particularly chronic degenerative diseases, humans face today. It was unapologetically a Darwinian paper. It has been cited 964 times.
Around this same time, in 1980, Paul Ewald, a zoologist, published Evolutionary biology and the treatment of signs and symptoms of infectious disease, which explored the implications of host-pathogen adaptations and the "potential importance of determining whether signs and symptoms are adaptations of the host, of the disease organism, both, or neither." The main focus was on acute disease. This paper is considered one of the first in Evolutionary Medicine.
Around this time, the Konner/Eaton team turned their work into a book for layman. Adding Konner's wife Marjorie Shostak to the slate of authors, in 1989 they published The Paleolithic Prescription: A Program of Diet & Exercise and a Design for Living. The book drew extensively from the fossil record of hominid evolution, as well as Konner and Shostak's own fieldwork with the !Kung, one of the last foraging societies that exists today (Shostak's books on this fieldwork are also a great read). It mentioned the word evolution 40 times. They also published a commentary together in 1989 Stone agers in the fast lane: chronic degenerative diseases in evolutionary perspective (PDF).
In 1991, evolutionary biologist George C. Williams and psychiatrist Randolph M. Nesse published a paper titled The Dawn of Darwinian Medicine, another pioneering work in Evolutionary Medicine that outlined methods for applying evolutionary biology to modern medicine, such as understanding "iron deficiency" as one of many potentially costly adaptations to a war between ancestral vertebrates and pathogens that has gone on for millions of years.
Many people seem to think that an adaptationist approach is based on the assumption that organisms are perfect. This is a misconception. It is true that the adaptionist holds the power of selection in high regard and is skeptical of explanations that take quick refuge in proposed defects in the organism. Paradoxically, however, the adaptationist is also particularly able to appreciate the adaptive compromises that are responsible for much disease. Walking upright has a price in back problems. The capacity for tissue repair has a price of cancer. The immune response has a price of immune disorders. The price of anxiety is panic disorder. In each case, natural selection has done the best it can, weighing benefits against costs. Wherever the balance point, however, there will be disease. The adaptationist does not view the body as a perfect creation, but as a bundle of compromises. By understanding them, we will better understand disease
The Eaton/Shostak/Konner team continued to refine their approach over time. The last paper they wrote together was An evolutionary perspective enhances understanding of human nutritional requirements in 1996, published after Shostak's death, along with her book recounting her last journey to visit the !Kung, Return to Nisa. 1996 also saw the publication of Nesse and Williams' book for layman about Evolutionary Medicine, Why We Get Sick (mentions evolution ~78 times).
Eaton and Konner started collaborating with exercise physiologist Loren Cordain and medical doctor Staffan Lindeberg. Cordain became particularly prolific on the subject, publishing a wide variety of academic papers and inspiring a Ray Audette's Neanderthin in 1998, which mentioned the word evolution 14 times. His own diet book, The Paleo Diet, was published in 2001 and mentions the word evolution roughly 11 times. Around this time you start to see intersection between the work originating from the Eaton/Konner paper and Evolutionary Medicine, with the original 1999 compilation Evolutionary Medicine edited by Wenda Trevathan containing Paleolithic nutrition Revisited by Konner, Eaton, and Boyd Eaton's son S. Boyd Eaton III. Nutrition was always part of both approaches and bringing them together influenced many later books and papers on the subject of evolutionary nutrition.
As you can see, the whole foundation of this was always Darwinian Evolution, the idea that humans share a common ancestor with all life forms.
Unfortunately, many Americans reject this. A recent survey found that only 39% of Americans accept evolution as fact. One of the reasons for this is in America, evolution has become politicized due to forms of powerful Evangelical Christianity that started promoting a reactionary anti-science form of Biblical Literalist Creationism (when I refer to Creationism, I refer to this) in the 1920s. Welding significant political power, they have managed to suppress the teaching of Darwinian evolution in public schools.
I have pointed out that Creationism and Creationists are harmful and incompatible with evolutionary nutrition. On Paleohacks, Karen from Paleo Periodical referred to this when she said: "I'm seeing the accusation that someone doesn't "believe" in evolution more and more, which strikes me as intolerably elitist (I say "believe" because I don't think evolution cares what you think about it)."
It's only elitist because Creationists have succeeding in making sure that most Americans are ignorant of evolution. There is no "believing" in evolution, there is accepting scientific evidence. And while you don't need to accept evolution to eat real food, evolution is the foundation of the paleolithic diet concept. So it is disturbing to see Creationists like Jimmy Moore framing debates within the paleo diet community. Over the past few years, he has moderated panels on paleolithic diet debates, published "state of the paleosphere" articles, and generally positioned himself as a person with clout in the "paleosphere." At some point he stopped just putting out podcasts with various paleo voices and instead stepped over a line into shepherding the paleo movement, which alienated many science-based paleo writers like Dr. Kurt Harris and many others, some who simply stopped describing themselves as "paleo" in lieu of a being part of a movement gutted of all meaning.
I do get hatemail for saying this and expect to get more. The latest letter said "Who cares if Jimmy Moore doesn’t believe in evolution? Truth is, there is not much to this Paleo “thing”. Exercise, eat like a caveman and reap incredible benefits." If you need a story about cavemen to tell you not to eat crap and that sprints are good exercise, I think we have a problem. There is already a "real food" movement among Christians. Go to Wise Traditions and you'll meet many of them, though a paleo dieter might have trouble convincing them of their common quasi-religious precept that grains are the devil. I think it's great when people start to eat real, whole foods. And there are many reasons to do so that have nothing to do with human evolution (even if a lot of the science behind them is based on evolutionary models).
But I also think that evolutionary models are important in biology and are the future of understanding what makes our bodies tick. It is more than about eating meat, fruit, and vegetables, it's can help us develop sophisticated treatment protocols for all kinds of diseases. It is sad for me to see that suppressed and stifled for marketing purposes. As Staffan Lindeberg said:
Why does the same thing happen to a piece of food after it has been swallowed by humans of different ethnicity? Why is the anatomy and physiology of the gut virtually identical in a Chinese and an African? Why do all human have the same endocrine system and metabolism? You know the answer: because we share an ancestor from way back when. The experts estimate that our latest shared ancestors lived around 200,000 years ago in Africa.
Before that, during millions of years of evolution, the digestion and metabolism of our primate ancestors had been fine-tuning how it uses the available food substances in the most beneficial manner possible. Nobody would doubt that the best food for the human species would be the kind of food that was available in those days, rather than those that were introduced long after the construction of our physiology. Funny that nutrition authorities never say it loud.
Our primate ancestors have been consuming fruit, vegetables, nuts and insects for 50 million years or more. Meat was successively added, with a probable increase around 2 million years ago. Underground storage organs (roots, tubers, bulbs, corms) possibly become staple foods 1-2 million years ago. The variability was large: single plant foods were rarely available in excess, which reduced the risk of adverse reactions to bioactive substances in plant foods.
I think loss of this is one of the reasons why more and more books are published on paleo that either contain nothing about evolution at all or have evolutionary narratives that seem pulled out of thin air. If the caveman stories are just stories, I suppose it doesn't matter to people much whether or not they resemble the Flintstones more than they do science. Paleo Diet guided by those who don't care about evolution is low-carb dressed up in a sexy leopard skin coat. By far, it's not Creationists who are wholly responsible for this, there is also a secular anti-intellectual slant that overemphasizes self-experimentation and scoffs at reading about science or at those who point out certain "facts" about evolution peddled by gurus are not based on anything but fiction.
The loss is ours, as the difference between caveman stories that tell us not to eat garbage and the adaptationist evolutionary approach is enormous. The former does rely on reenactment of some golden age in which humans lived according to our design. Is it any coincidence that this resembles the story of Adam and Eve? In contrast, the adaptationist approach is one in which species are constantly under pressure and must adapt. Some of these adaptations are imperfect and even costly. It is possible we can do even better by thwarting some of these adaptations through modern technology. Evolutionary medicine isn't just about eating like your ancestors, it's possibly about outrunning some of the adaptations that cause things like aging through pharmaceutical or even cybernetic augmentation. It's not regressive like some calls by various authors like Lierre Keith to give up our technology and return to the Stone Age, it's cutting edge, even daringly post-human.
We have the opportunity to be on the front lines to show that evolution is important to humans now, that evolution, by enhancing our understanding of ourselves, can improve the way we live.
Some have also accused me of discriminating against Christians. As far as I'm concerned, Jimmy is welcome to learn more about biology and join the millions of Christians who are not anti-science. I made that journey myself, having been educated in Creationism as a child, with such anti-science absurd books like It Couldn't Just Happen. I was reading the reviews for that book on Amazon and it's interesting how many other people grew up with that book, but later learned more about evolutionary biology. Some became disillusioned atheists, others realized you don't have to be a Creationist to be Christian. Christians have been fighting Creationism for a long time. A notable example is Orthodox Christian Theodosius Dobzhansky, who wrote the essay Nothing in Biology Makes Sense Except in the Light of Evolution in 1973 response to anti-evolution Creationists:
Does the evolutionary doctrine clash with religious faith? It does not. It is a blunder to mistake the Holy Scriptures for elementary textbooks of astronomy, geology, biology, and anthropology. Only if symbols are construed to mean what they are not intended to mean can there arise imaginary, insoluble conflicts. ...the blunder leads to blasphemy: the Creator is accused of systematic deceitfulness.
It's funny awhile back someone recommended that I just attend some less extreme churches than the ones I grew up in, just to see what it's like to go to a church that doesn't spend time preaching against homosexuality or evolution. Because at that point, that was really the only Christianity I knew. I really enjoyed going to those churches and met a lot of wonderful people, people who generally do not take Genesis literally, people who do not reject evolutionary biology and in fact some who work as evolutionary biologists! I also have learned much about the history of Early Christianity through attending Orthodox churches and it was stunning to me to realize how divorced modern Evangelical Christianity is from those roots or understanding how the Bible was put together by humans. I also came to question many things "paleo" dieters accept almost religiously as facts. Did you know that the monks on Mount Athos live long lives free from modern disease thanks on a diet that is pretty much vegan and high in grains? It is possibly partially due to ancient Christian fasting traditions.
I think American Creationists (and people who think Christianity requires such nonsense) could use some history lessons on their religion, the Bible, and on life itself. As priest Pierre Teilhard de Chardin said "Is evolution a theory, a system, or a hypothesis? It is much more it is a general postulate to which all theories, all hypotheses, all systems much henceforward bow and which they must satisfy in order to be thinkable and true. Evolution is a light which illuminates all facts, a trajectory which all lines of though must follow this is what evolution is."
If you are interested in learning more about how human evolutionary origins shape us today, some great books for anyone to read are Your Inner Fish, Written in Stone, Why Evolution is True, Why We Get Sick, or Before the Dawn, especially if like me, you did not learn much about evolution in grade school. Talk Origins is also a good resource.
In academia, Evolutionary Medicine continues to thrive. It has a society and many different conferences. It is also too bad that so many interesting and relevant evolutionary medicine/nutrition resources are so expensive. Many books on the subject cost upwards of $100 each. Two extensive papers were just published on the subject. One is $45, thank goodness the other is free, which is very unusual. But why aren't these folks publishing writings for laymen like the original pioneers of evolutionary medicine and nutrition did? As we discover more and more about how humans evolved, books become outdated quickly, so perhaps they should consider blogging rather than books.
I'd love to see more writings for laymen by them and more writings not afraid to mention evolution and even to educate readers about it. I think such interactions would not only be beneficial for us, but for them, since I feel the online community in particular can generate hypotheses faster than in academic publishing. You can see some academic researchers, like anthropologist Miki Ben Dor, drawing on hypotheses that have primarily been pushed by the online community like the idea that larger amounts of fat might have been more important in hominid evolution than previously thought.
Edit: here is a great editorial written by Randolph Nesse and Detlev Ganten recently:
The human body is a living archive of evolution, written in our genes, cells, and organs. The line is continuous to the beginning of life on this planet, so nature is inherently conservative. Sequences that are ancient parts of our genomic heritage tend to persist. Those important for survival and reproduction change less over the eons, so genes important for basic functions are generally “old” genes. The basic mechanisms that regulate cellular metabolism, cell division, and gene duplication are fundamentally the same as those occurring in unicellular organisms at the beginning of life on earth 3.5 billion years ago. Likewise, the molecules, cellular functions, organs, complex organization of muscles, bones, sensory organs, and nerves in vertebrates derive in an unbroken line from ancestors millions of years ago. Much of modern man's biology dates back to the origins of life; a complete understanding of this biology can only be appreciated with an evolutionary perspective .
We are not "designed", we are "adapted," and adaptations can be incomplete and imperfect. It matters less what our ancestors ate, than what selective forces were at play and how we adapted to them. Such a paradigm can help us see the costs and benefits of something like getting large amounts of calories from meat, which humans are definitely not perfectly adapted to, which is possibly responsible for such diseases as hemochromotosis.
Edit: Also worth reading is evolutionary biologist Michael Rose's 55 Theses on using evolutionary biology to improve your health, particularly in understanding (and possibly beating) aging.
In my last post, I wrote about how it's impossible for epigenetic changes from very cold environments 3-4 billion years ago to have been conserved. Somehow people thought I was accusing Dr. Kruse of making up cold-adapted monkey ancestors or something.
No, I realize he doesn't mention cold-adapted monkeys, but he also doesn't stick to bacteria living in sad cold slurries either. He also mentions ancient mammals. Dr. Kruse also has an interesting belief that all mammals “evolved in the polar environments on earth.”
I can't find any evidence that early eutherian mammals evolved in such an environment or even a later candidate for a polar eutherian that could be a possible ancestor. They discovered the earliest known (so far) eutherian fossil last year in China, Juramaia sinensis, in a Late Jurassic formation. The climate in the area at the time was relatively warm and dry. Juramaia sinensis' teeth suggests it was an insectivore. Many other early mammal fossils have been found in Asia, but as we know, mammals went on to colonize a variety of environments and climates.
Dr. Kruse says "mammals were ideally adapted for hibernation too, until they got too smart for their own genes sake.” It is indeed true that Juramaia sinensis and other early eutherians did hibernate. Mevolutionary biologists now consider the origin of biological changes distinct to hibernation behaviors to have originated even before the evolution of class mammalia and are displayed even in reptiles who live in very warm environments.
Why did most mammals stop hibernating then? As the excellent paper The Evolution of Endothermy and Its Diversity in Mammals and Birds says “ energy-optimization-related selection pressures, often dictated by the energetic costs of reproduction, apparently favored abandonment of the capacity for short- or long-term torpors." In most primates, it seems this abandonment was characterized by a species with a large brain and increased adaptability to a variety of foods and climates.
That's too bad, because hibernation (or even torpor, a less extreme form) would be very useful for things like organ transplantations, surgery recoveries, or long space flights. In the future, if we figure out how to do it, being able to trigger hibernation would be incredibly useful. Unforunately, the exact way to trigger hibernation is not currently known, though there are many promising candidates. Dr. Kruse however believes that the stimuli is already known: “the stimulus for hibernation in eutherian mammals and their descendants are tied to high dietary carbohydrate intake (proven fact already in science and not controversial).” If only it were that easy. A search of the scientific literature found no papers that posited that carbohydrate consumption triggers hibernation, though it is established that carbohydrate metabolism undergoes changes before and after hibernation. Scientists who propose triggering hibernation believe it would probably involve injection of chemicals produced by hibernating animals. This would be possible because many of the genes related to hibernation are still present in primates, not because we hibernate, but because they have other functions. We'd also have to figure out how to prevent brain damage, which has been a major challenge to such research since humans appear to suffer memory loss from brain changes normal to hibernating mammals.
Evolution is efficient and while genes that had interesting past uses (wouldn't it be cool if we could "reawaken" gills or the ability to lay eggs??) are often conserved in our genome, they are often expressed in radically different ways. It seems the areas that once encoded for gills, for example, are now related to the bones in the ear. As for those that don't seem to be in use now, as geneticist Paul Szauter says:
If genes are not expressed in the human genome, they do not survive intact over evolutionary time, because they accumulate mutations in the absence of selection. If there were squid genes in the human genome that could be "activated," it is likely that the accumulated mutations would result in a truncated gene product (3 of the 64 codons are "stop") with many changes in its sequence.
Dr. Kruse believes that humans, like all mammals, are optimized for hibernation and that remnants of mammalian hibernation are activated in humans based on certain times of the day: "It appears 12-3 AM are the critical hours at night are where the remnants of mammalian hibernation lies for our species". This is a far cry from the current state on literature related to hibernation. The idea that remnants of hibernation occur in humans at night also goes against the definition of hibernation. An excellent paper authored by another McEwen, Dr. Bruce McEwen, has a great concise definition "Hibernation is a highly regulated physiological response to adverse environmental conditions characterized by hypothermia and drastic reductions of metabolic rate"
Re-definition and special unique definitions of terms is another of Melia’s characteristics of bad books: “ The texts of these books all continue in the same excited first-person voice. They often introduce vague, undefined or invented terms.” A good example of this is in Dr. Kruse’s PaleoFX talk, where he references “ geothermal circadian cycles.” It sounds scientific, but there are no known circadian cycles that are tied to Earth’s internal heat* and it appears Dr. Kruse invented the concept since it is found nowhere else. It is a particularly deceptive practice, made easier by the fact that many of the terms that are often mis-used by these authors, such as the species concept or even hibernation, are the subject of some academic contention. But while academics might be arguing about whether or not bears are “true hibernators,” we can be assured that no one is considering that humans are hibernating every night because that doesn’t even fit into the realm of contention or the fringes of what is considered hibernation.
The only known primate that hibernates is Cheirogaleus medius, member of suborder Strepsirrhini, which diverged from the evolutionary line that led to humans over 70 million years ago. They also store a lot of fat beforehand, so I don't know if I'd like to hibernate like them anyway. I don't think I'd look so good and I probably wouldn't get much work done.
Even if it were conserved, Dr. Kruse makes the mistake of tying hibernation to extreme cold: “Cold environments are found as mammals hibernate in normal circadian biology…….this completely reverses IR in mammals and wakes them up when conditions are better for life.” Dr. Kruse’s cold therapy involves exposure to freezing temperatures, because he thinks that is linked to hibernation in humans. Kruses asks his readers if maybe diabetes has “become thought of as a neolithic disease in humans because we we have simultaneously lost the ability to hibernate because we evolved the ability to control our environment completely?” However, there are many animals that hibernate without exposure to very cold temperatures and biologists are still debating whether or not relative cold is even needed to trigger hibernation at all. For example, the only hibernating primate, the aforementioned Cheirogaleus medius, hibernates at 30 degree celsius (86 F). And if humans had lost the ability to hibernate because we control our environment, we would find the ability in related primates who do not control their environments. But we do not. The northernmost living non-human primate, Macaca fuscata, does not show any evidence of hibernation or even torpor, even those that do not visit hot springs. Interestingly, their winter diet does include digging for roots.
Why do so few primates hibernate? Around the equator, where primates evolved, seasons operate quite differently than they do in the arctic and other regions far from the equator. Because the environments and climates of Africa are so diverse, with many micro-climates in certain regions, most primates closely related to humans have evolved to be able to adapt to scarcity regardless of Earth’s axis tilt through the reliance on “fall back foods.” Possibly because of this evolutionary strategy, there is no particular dietary pattern that consistently characterizes the seasons for primates as an order or even within species.
Even in non-primates that live in the north, a very small percentage hibernate. For example, some squirrels hibernate, some don't. Those that don't often will cache food and eat it later. Some humans are known to raid rodent caches for carbohydrates. This contrasts with Dr. Kruse’s idea of seasonal biological changes being triggered by changing to carbohydrates or one season being devoid of carbohydrates: “it appears that dietary carbohydrates, which are only present in long light cycles in the summer in cold places, induce mammals to add PUFA’s to our cells to become fluid so we can function as we hibernate.”
According to Kruse, since carbohydrate consumption is tied to hibernation in cold environments, since we don’t really hibernate now (except sort-of, at night according to Kruse), carbohydrates might not be safe to consume: “Since we no longer hibernate……..maybe you need to consider how you eat carbohydrates within the circadian controls? Maybe what you thought was safe………really is not?” The implication is that carbohydrate consumption is only “safe” for mammals in the context of nature’s “design” for hibernation. In terms of our evolutionary line, that makes little sense. The vast majority of primate species consume diets of mainly carbohydrate, with two main digestive strategies. The evidence is that ancestors of modern hominins relied on a mainly-carbohydrate diet until somewhat recently.
If Dr. Kruse’s line of reasoning is true, most primates are living out of balance with nature and have been for millions of years. Some of his followers have said that this only applies if you live in the north since there are somehow some circadian controls only in the North that are tied to carbohydrates (zero evidence provided), but then the mice and squirrels who are eating stored or underground roots are violating natures law. And the idea that if you put an individual primate in the north that it will change its underlying biology to fit the north's light cycles does not have any evidence behind it (and in fact the fact that individual humans don't adapt particularly well to northern light cycles is perhaps behind the etiology of many modern illnesses).
As I will write in my next post, some human populations (and possibly other hominin lines) have genetic adaptations to more polar light cycles, but these are recent adaptations and are not shared by all humans. And one unique thing is that humans that inhabit cold regions have a raised metabolic rate during the coldest season, not a lowered one characteristic of torpor or hibernation, which suggests adaptations more similar to those found in wolves rather than ground squirrels**. Also, I must also discuss longevity being derived rather than ancestral. But I'll leave that to the next post.
* Geothermal according to the OED is “ 1. Geol. Relating to or resulting from the internal heat of the earth; (of a locality or region) having hot springs, geysers, fumaroles, etc., heated by underlying magma.””
** are non-hibernating squirrels naughty "nature's law" breakers? Particularly if they are eating stored carbohydrates?
In my last post on the subject of Dr. Jack Kruse, AKA, The Quilt, I briefly touched on the misuse of the ideas of quantum theory. Not long after, the WSJ had an excellent article on the mis-use of that subject.
Actually, it's pretty interesting because I agree that both the mis-use of evolutionary biology and quantum science aren't that bad, because they show that people really are interested in science. They are just suseptible to bad science, which isn't a surprise considering the abysmal state of scientific education in this country. Only about 4 in 10 Americans actually believe that evolution is a real thing.
Well, here is some background for new readers. My original post confused some people who do not post on Paleohacks, where my rivalry with Dr. Kruse has a very long history.
The question of what drives popular interest in such evolutionary fantasies is a difficult one. Frequently, they are bundled in with good advice, further increasing credibility among laymen. They contrast with legitimate evolutionary biology in that they contain simple and often epic “just so” narratives that appeal to people, in contrast with the complexities and fervent debates in the academic study of human evolution.
An example of one such internet popularizer is the aforementioned Dr. Jack Kruse, a Tennessee neurosurgeon and dentist who started plying a “paleo” diet and lifestyle program called the Leptin RX Reset on various popular paleo diet websites (particularly Mark’s Daily Apple, which is ranked 2000 on the Alexa web traffic rating system in the US, and Paleohacks, which is ranked 8000) in 2010. Calling himself “The Quilt,” his posts quickly became some of the most popular on these sites. In June of 2011, he launched his own website, containing a blog and his master “Quilt” manifesto and cracked Alexa’s top 100,000 sites in the US within months, hitting 26,581 in March 2012. He gained a further audience from the online Paleo Summit, where his talk was among the most popular and where many people learned about the next part of his Leptin RX Reset program, the Cold Thermogenesis Protocol (CT). Then he was a keynote speaker at PaleoFX, an Austin paleo conference sponsored by The Ancestral Health Society that drew many of the movement’s most popular speakers. In the fall of 2012, he will be a panelist on a debate about “safe starches” at the Ancestral Health Society’s main conference, the Ancestral Health Symposium.
Evolution is central to Dr. Kruse’s ideas and recommendations. In a comment to reader he explained “ Adapting evolutionary biology to what we learn makes us a better physician not matter what we do.” His writings contain many references to human evolutionary origins and how his readers can use them to improve their health in a modern context. Many of his readers have reported success from using his recommendations, but is the evolutionary basis behind them sound?
During a panel at PaleoFX in Austin Dr. Kruse said
Only humans who fail to listen to evolutions rule book of engagement die. You can eat a banana in the winter and feel fine but Mother Nature says it’s impossible………therefore we ought not to do it. I will follow her lead over a diet book guru or the opinions of a bunch of people who let their thoughts subjugate their genes. Feelings and thoughts do not trump neural biochemistry …
But his writings reveal a more ambivalent view of evolution. On one hand, on one blog post he says that “The speed of evolutionary change has far out stripped the ability of our paleolithic genes to catch up.#” But in his Quilt manifesto he outlines an extremely plastic view “A human is the only animal that can actually change its DNA just by thinking. Moreover, what we really think is just a biologic secretion. No different than any hormone released by the pituitary gland. Thinking is… well it is a meme that hijacks our brain’s chemistry. Any one thought can alter our genetic and biologic purpose in life.#” Therein lies an essential paradox- on one hand our genes are “paleolithic,” but on the other they are malleable simply by thinking differently. Perhaps it is just part of our genes that are “paleolithic.” For example, he refers to our brains being neolithic and able to “subjugate” our paleo genes, with negative consequences: "our neolithic brains allow us to make decisions that subjugate out paleolithic genes all too often.”
The idea that human genetics have not changed since the end of the Paleolithic roughly 10,000 years ago and that they are mismatched to the modern neolithic environment is a common one in paleo diet circles. Unfortunately, its origin can be traced back to academia and it lives on as a popular principle despite the fact that it has been the subject of considerable controversy in evolutionary biology. A common citation in paleo books is to An evolutionary perspective enhances understanding of human nutritional requirements, a paper written by Boyd Eaton, Melvin Konner, and Marjorie Shostak in 1996:
Geneticists believe that the increased human number and mobility associated with civilization have produced more, not less, inertia in the gene pool and that when the humans of 3000-10,000 years ago (depending on locality) began to take up agriculture, they were, in essence, the same biological organisms as humans are today (Neel 1994).
More recent research has come to the opposite conclusion, as newer statistical genetics models have actually found that human evolution has accelerated greatly in the past 40,000 years, certainly not freezing with the advent of agriculture. However, along with many other paleo authors, Dr. Kruse is still of the less dynamic mindset, writing that “Evolutionary pressures are selected for by the environments of our ancestors were exposed to and not for what we face today.”
n academic anthropology, new discoveries in archaeology and rapid advances in genetics have spawned a discipline in which textbooks are outdated as soon as they are published. Human origins are constantly under debate, which means that even if scientific education were adequate in the US, it is fairly hard for anyone to keep up. But even a basic outdated education on the topic would help a layman be critical of several pop-science fringe evolutionary theories that have cropped up, such as the “aquatic ape” theory. Why do such theories become popular? As anthropologist Jim Moore put it:
Even among scientists, as we've seen with Hoyle, there are times when assertions are put forth which are poorly drawn, yet, because they strike a chord, often of wishful thinking, they catch on and are repeated. Yet refuting them can be an exercise in futility. A good scientific review and critique is a lot of work, and takes a lot of time. But it's far easier to pop off with a theory that's poorly researched than it is to accurately go over all the things that the original theorist should've, and to provide a point by point refutation.
In the case of the Aquatic Ape theory, Jim Moore did a major service by creating a website to refute it, since as he elucidates there, there is very little incentive for academics to engage in debates with popular pseudoscientific theories, since they are so focused on doing their own original research for the benefit of their careers.
This is unfortunate, because pseudoscience has great power to shape the public’s consciousness. As anthropologist John Hawks puts it:
Is the Aquatic Ape Theory fairly described as pseudoscience? Every statement of natural causes is potentially scientific. What distinguishes science from pseudoscience is social. Pseudoscience is supported by assertions of authority, by rejection or ignorance of pertinent tests, by supporters who take on the trappings of scientific argument without accepting science's basic rules of refutation and replication. Pseudoscience is driven by charismatic personalities who do not answer direct questions. When held by those in power, like Lysenkoism, it destroys honest scientific inquiry. When held by a minority, it pleads persecution.
In a world where many people are unhappy and unhealthy despite our scientific advances, the idea that conventional science is wrong can be quite appealing. It allows people to buy into fringe pseudoscience for which little evidence exists and not question the lack of evidence.
Dr. Kruse has a new interesting spin on the "paleo" diet, though whether his approach is "paleolithic" is up for debate. His spin on the evolutionary approach lately has emphasized cold. Why?
Considering that 90% of the earth’s current biome lives in extreme conditions on our own planet today still, we might need to consider that what we think is “our normal environment” is not so normal for most of life on our planet or our evolutionary history. Life on Earth evolved in an environment much like we see on Titan today; in a deep ocean frozen solid at its surface with the capability of life buried deep with in it. The only escape was due to ejectants of water vapor from super heated water from underwater volcano’s. All these things are present today on Earth’s crust too. There is one major difference now between the two. We are warmer today than life began. There are others, but when one looks at Titan we see a frozen giant moon with a monsterous ocean beneath it.
This creates an issue of whether or not Dr. Kruse is even promoting a paleo diet or if instead he is promoting a Archean diet. But if he is referring to the Archean, it is mystifying that he emphasizes cold, considering that the Archean was probably warmer than today. Dr. Kruse has "references" on his blog, but I would challenge anyone to tie the meandering list on his blog post with any actual "facts" in his writing, like that cold promotes autophagy or that Neuropeptide Y is downregulated in cold weather.
Either way, debates as to the origin of life on Earth are still happening, with some (but not a consensus!) emphasizing the possibility that colder temperatures were the ideal place for single-celled life forms to originate. Dr. Kruse believes this is important because “life first adapted to extreme environments and then was naturally selected and adapted to a cyclic warming trend on our planets crust over time.” But he seems to believe that this adaptation was somehow incomplete: “Our hominid species may have adapted during this warming trend, but the DNA we inherited came from animals that were cold adapted.” Did DNA not adapt during this warming trend even through our hominin ancestors themselves adapted? It seems strange since Dr. Kruse believes that “One thought might just alter your DNA!”
Instead, he believes that these adaptations were mostly epigenetic, once again appealing to the idea that he knows more than conventional science “We know today that the power of epigenetics dictates a lot more about newer generations adaptations than we even knew ten years ago.” While epigenetics has become an important field, it is clear that a species adaptation to changing environments involves both epigenetic and genetic adaptations. Unfortunately, epigenetic is an appealing buzzword, which has been co-opted to absurdity. Dr. Kruse says that the warm paleoclimate that our primate ancestors were exposed to might not matter as much as we think it does because we might still carry an epigenetic imprint from the cold that engulfed Earth 3-4 billion years ago:
The modern science of epigenetics shows that who we came from and what they faced has a direct biologic effect upon subsequent generations DNA and phenotypes. It is crystal clear today, but the biologic implications remain unexplored in all modern day literature. What is happening on Titan maybe like opening up a blackhole back to a reality that used to be our own. The ability to see Earth at life’s evolutionary beginning.
This is confusing, because while here he blames epigenetic relics, in other writings he blames static genetics: “ The speed of evolutionary change has far out stripped the ability of our paleolithic genes to catch up. This mismatch causes major problems for modern humans.” Dr. Kruse seems to want to have it both ways.
The idea that epigenetic relics from billions of years ago are affecting us today is questionable, since the latest evidence shows that epigenetic changes are not stable enough to carry on from thirty generations and certainly not from 3-4 billion years ago. Evolutionary biologist Jerry Coyne has addressed people who hype up the evolutionary significance of epigenetics: “ There are a handful of examples showing that environmentally-induced changes can be passed from one generation to the next. In nearly all of these examples, the changes disappear after one or two generations, so they couldn’t effect permanent evolutionary change.“ This is in direct opposition to Dr. Kruse’s view of how evolution works:
I think evolution found that epigenetic modifications to be quite effective way to pass on environemental information to succeeding generations. So successful that it became a backbone law of genomic functioning. Evolution follows fractal patterning. So it is also highly conserved in all species. Today that appears to be true too.
While epigenetics has indeed led to important new understandings, it is less of a game-changer than Dr. Kruse presents: “Evolution uses epigenetics to determine adaptation to environments. We have discarded the strict definition of genetic determinism that came from Watson and Crick, as founders of DNA.” As evolutionary biologist Rama S. Singh succinctly put it:
While the new discoveries of the laws of developmental transformations are enriching our knowledge of the intricate relationship between genotype and phenotype, the findings of epigenetic inheritance do not challenge the basic tenets of the neo-Darwinian theory of evolution, as other than producing new variation no new processes of evolutionary change have been added to the ones we already know — mutation, migration, selection, and drift
Unfortunately, Dr. Kruse’s erroneous beliefs on human evolution have wide-ranging consequences holistically on his philosophy and recommendations, since it causes him to believe in conservation of many traits for which there is no evidence of conservation in Hominidae. Daniel F. Melia, professor of Celtic studies, recently wrote an article about characteristics of bad books that promote pseudoscience in his discipline. One of these characteristics is “Confident conclusions are often the result of chains of circumstance and supposition so long that even remembering their origin points while reading the books is difficult.” It’s easy to see that here and it shows how particularly ingenious this characteristic is since it makes anyone who tries to criticize the absurdities wade through the mire, further dis-incentivizing criticism.
A reasoning that Dr. Kruse uses for carbohydrate restriction is that epigenetics has sped up: “epigenetics has sped up and you eat a warm climate diet you by definition increase mitochondrial ROS that slowly kills you” A search of the scientific literature and academic databases found zero papers on epigenetics speeding up in modern humans. His article cites Wikipedia and himself.
The phenomena he blames on an epigenetic speed up also often do not have known epigenetic causes.
This is more fuel or proof that the “metabolic trap door” I found makes all starches less safe when they are eaten outside how our circadian biology accounts for them in our sped up systems. Evolution power laws has sped up too simultaneously to compound the issue. This explains why kids today are huge and bigger than their preceding genrations. It explains also why they reach puberty faster today.
Scientists are not sure what is causing earlier puberty(NYtimes article yesterday). If Dr. Kruse really knows, he should be eligible for a Nobel prize. It’s also interesting because paleo authors are often quick to point out that Paleolithic humans were bigger and stronger than modern humans because of their healthier diets and lifestyles. Yet Dr. Kruse is portraying this phenomenon as a bad thing, which begs the question as to why the paleolithic humans were bigger. Were they eating too many carbs? Why modern humans are catching up to paleolithic humans in terms of height is a matter of debate, but the best theory is it has to do with greater access to calories and less malnutrition stress.
Overall, on the issue of genetics and epigenetics, Dr. Kruse seems willing to rewrite definitions and build a pseudoscientific narrative that has little basis in reality. It shows that new scientific discoveries that become buzzwords in the public consciousness are very easy to manipulate in order to build such narratives. They make them sound scientific and cutting-edge, when in reality they are empty and devoid of factual basis.
I have MUCH more to write on this subject, including more on the evolution of mammals, hibernation, and hominin adaptations to cold. Also, a history of how he did not invent most of the regimens his followers praise so highly, as well as the actual non-pseudoscience evolutionary biology reasons that they work for those people.
I usually don't like to watch people speak about stuff. Maybe that's why I almost never went to lectures in college. I prefer to read things. As Data from Star Trek might say, I find it to be the most efficient form of assimilating information. So you can watch my talk on Vimeo thanks to AHS, but if you read much faster (or you are hearing impaired), you can read the transcript below, which was donated by Averbach Transcription, which is run by a paleo enthusiast and you should consider hiring him if you need a transcript:
[applause] So, hi everyone. I was at Mat Lalonde's talk this morning, and I was thinking, "How am I going to introduce myself, what are my credentials?" And I don’t really have any. I have a degree in agriculture and I study anthropology currently at Columbia University, but I'm not in the Ph.D. program.
But I have had the pleasure to study with Professor Ralph Holloway, who's a really excellent physical anthropologist, and he inspired a lot of this presentation. And I have a website, it's called huntgatherlove.com, and you can visit it, and I have also a lot of the stuff from this presentation is there, and a lot of the references to the papers, if you want to read the original ones.
And yeah, I'm not a core scientist, but my boyfriend Chris is, and I try to study, you know, remind myself that chemistry and biology are really important even in anthropology, and I think a good physical anthropologist tries to really incorporate that into their studies.
What is so special about the human gut? Why do we care about it? Why don't we just eat like this nice ape in this picture on the left and just eat some healthy, high-fiber diet, which is low in fat? Just eat like a salad, because everyone knows that salad is really really healthy.
Well, the problem is we are not like gorillas; we're great apes, we have a shared history with gorillas, but we have our own unique niche. And I think when I'm reading a lot of the literature on evolutionary health, I'm seeing these different viewpoints. One I'm going to call statics, and it has an emphasis on what has been conserved from our evolutionary past from some time period, often which is defined somewhat arbitrarily.
And it also focuses on primate relatives such as gorillas. You know, we're great apes, they're great apes, we should eat like them maybe. And I think of course they have very interesting lessons, but I'm going to emphasize more the dynamic view of evolution, the emphasis on unique adaptations that humans have to their own niche, and our continuing evolution even now.
We're evolving as we speak.
So the static viewpoint is that the ancient human diet of some timespan, you know, Precambrian, Upper Paleolithic, was the optimal human diet. And there was a great deal of emphasis on the fossil record. Professor Holloway always likes to say, "When you look at the fossil record, sample size equals two, because there's not that many fossils from certain periods."
You know, we have part of a cranium and that's it of some periods. So it's pretty hard to abstract from the fossil record. And also emphasize related species that we share a common ancestor with. And a lot of times some of this research comes to the conclusion that a high-fiber diet consisting primarily of plants is optimal, and that everybody, every human being should be able to eat this way and be healthy.
There's a lot of Paleolithic Diet papers, but why not the Cambrian Diet? I mean that was a really long timespan, it was 52 million years versus like two and a half, and these creatures look perfectly healthy to me, and they seem way healthier than I am.
Here's a quote from Stephen Jay Gould that, I was a fan of Stephen Jay Gould for a long time, and I still admire him, but I don't agree with this quote, that, "There's been no biological change in humans for the past 40,000 or 50,000 years. Everything we call culture or civilization we built with the same body and brain."
And I thought Stephen Jay Gould was just this nice guy who talked about dinosaurs, but actually Professor Holloway told me that he has some questionable stuff in his research, and that idea that humans haven't changed for a long time is one of those. Another one is that he denies modern human variation quite strongly.
He has this idea that we're mostly the same, which in some ways is true; in some ways it's not true. And I think it denies the fact that we can gain a lot from looking at continuing evolution. And the dynamic view, which I'm going to talk more about, is humans are unique among the great apes, and recent human evolution has led to important changes, especially in digestion.
And besides our own genetics, we have the bacterial microbiome, and our evolution in that has been even more rapid, because bacteria have many more generations, they reproduce faster than we do. And there's high variation among modern humans, particularly with a growing population and introduction into new environments.
So there's probably high variability in [their optimal diet]. And a book that's been a big influence to me is "10,000-Year Explosion" by Gregory Cochrane and Henry Harpending, and it's, "How Civilization Accelerated Human Evolution." And it has pretty convincing evidence that human evolution not only didn't stop 10,000 years ago at the end of the Paleolithic; it's continued to accelerate greater and greater because of all this new environments and greater populations, and also the changes in culture and technology that have happened since then, which have been very rapid.
And in dynamism we have these four keystones I like to think about. One of them is our unique anatomy. Another one is our unique cultural behaviors. Another is our unique bacterial microbiome, which isn't shared with any other primate, and each person has a unique one. But also just in general a very high variability among humans.
And a lot of this is relatively unexplored because it's very controversial. It's hard to get funding. I've met people who do studies on human variability who can't publish them because they're so controversial.
And especially very important in unique cultural behaviors is a shift towards exogenous food processing. So in humans, in our evolutionary past, we processed food inside of ourselves, but in modern humans and in our evolution towards modern humans we have a shift towards processing food outside the body with cooking and grinding and soaking and all these other processes.
So when we're thinking about human evolution, we have to think of—this is an estimate of cells in the human body, and that there's maybe 10 trillion human cells and 100 trillion bacterial cells. And these bacteria are evolving faster than we are. And they're very very important.
They process nutrients, they produce nutrients, they fight off infections, are an important part of our immune system. They have a role in nearly every disease, even diseases you might not even expect, such as heart disease. There's a new paper that shows that metabolites produced by certain gut bacteria that some people have and some people don't have, in response to certain foods, can produce things that are implicated in heart disease.
And also, behavior. I mean, we can't do many of these studies in humans because they're unethical, but in fruit flies if you change the gut bacteria, you can change their sexual orientation. And you can understand why we can't do that experiment with humans; that wouldn't be good.
So there's several factors with these bacteria, and we have to think about interspecific competition—competition between different species, which is driving a lot of this evolution, intra-specific competition—so within even one species, you have tons of strains that are very different, and they're competing with each other, often in one person.
You can have several strains of one bacteria within you at one time. The host function, our own unique anatomy and genetics; our host fitness, which is quite important nowadays, now that a lot of people aren't as healthy as they once were. Particularly in the gut, there's a lot of people with dysfunctional gut permeability, which really affects the bacterial population.
You have food ingested by the host, and you have the metabolites themselves in microbiota, which is tons of different chemicals and fatty acids. And quite important for humans but not unique to humans is culture and technology. These can affect the gut microbiota too.
And there's a bunch of papers that are quite interesting that have more of a static view, and static's this view that we're going to look at other great apes and see what we should eat today. And I think a lot of this research is very admirable, but I think sometimes they come to conclusions that don't make sense in the light of our own unique anatomy.
One of them is Nutritional characteristics of wild primate foods: do the diets of our closest living relatives have lessons for us by talented primatologist Katharine Milton. Then you have this paper, "The Western Lowland Gorilla Diet, are there implications for health of humans. "
And here's a sample sentence from a paper like this, this paper is called "Case Closed: Diverculitis, Epidemiology and Fiber." It says, "The western lowland gorilla, whose diet may approximate a Paleolithic human diet, has an estimated intake of nearly 60% of its calories through the colon," and the second part of this sentence really puts a question mark on the first part:
You can see that this is quite interesting about gorillas. You know, they eat a diet very high in fiber, and it's all plants, pretty much, and they're getting a lot of carbohydrates in the diet, ingesting in their mouth. But then their colon, the bacteria in the colon is this giant bio-reactor. It's turning this carbohydrate, this fiber, this otherwise indigestible fiber into something called short-chain fatty acids.
And short-chain fatty acids are providing over 60% of calories for the gorilla. So the gorilla is eating a high-fat diet, actually; it's just not eating the fat directly. It's turning the carbohydrates that it's eating into fat, fatty acids.
And humans are quite different from other great apes. Here's a famous paper called "The Expensive-Tissue Hypothesis" by Aiello and Wheeler. You can see they did some linear regressions that looked at, based on other primates that we have data for, what should human organ weights look like?
And here's the expected human organ weights, and here's the observed. And what is different? Look how big our brain is and how small our gut is. But even within our gut, there's reorganization, and the reorganization, the driver of this is this food quality. And when I talk about food quality, I'm not talking about [Hardee's] versus Whole Foods; I'm talking about caloric density.
And with this high caloric density, there's less need for this processing equipment that's internal, these internal organs. And so energy is freed up for other organs, such as the brain, in this expensive-tissue hypothesis.
In this gut-brain tradeoff, you have higher diet quality, increased energy availability, and so larger brain. The small gut with the higher diet quality also frees up energy; larger brain. And more complex foraging behaviors, which keep enable… It's driving like a feedback cycle. You know, the more energy we're getting for our brain, the better—the bigger our brain is and the smaller our gut can get.
And you can see that the organization of the gut too, versus other primates—you have all these great apes here, and you have humans here, and look at the human small intestine; look how much bigger that is compared to the other great apes. And the colon is so much smaller. And you can see this in this chart from the Beyond Veg site, which is a great site.
You can see the chimpanzee has a quite long, well-developed colon. The orangutan does as well. But look at the human colon—it's very under-developed and small compared to these other apes. And we're not sure when this change happened in our evolutionary history. It's not like you can find frozen Paleolithic apes very easily.
But we do have this gut—in the post-cranial anatomy you have some indicators that might correspond to a smaller gut or a larger gut. And here is a chimpanzee here, a modern human here, and Australopithecus afarensis, living around maybe 2-3 million years ago, perhaps one of our ancestors.
And you can see this funnel shape in the ribcage, and a large pelvis, which could accommodate a bigger gut. And humans have this defined waist, which we also find very attractive in humans, and a smaller pelvis. And here's some of these apes stripped down, where you can see this giant gut in the gorilla, and the chimpanzee has a pretty bit gut, and an orangutan does.
Humans and gibbons do not. Gibbons are frugivores, so they eat a higher-quality diet than even the more leafy, kind of sticks and stuff that these other apes eat. And here's a human waist—very small compared to the other great apes, except for the gibbon.
And so in humans, how much do we get from short-chain fatty acids? How much do we get from the colon? The colon's smaller. And the human current maximum estimate is maybe nine percent from short-chain fatty acids. So if we go and eat a gorilla diet, we're not going to get as much out of it as the gorilla does.
We'll probably die if we just eat leaves because we can't turn it into short-chain fatty acids with the efficiency that a gorilla does. We don't have the equipment. But I must add a caveat to that. Most of these studies have been done in Westerners, and there's this new hypothesis floating around in papers, this idea that Westerners are the weirdest people in the world—and we are.
Our culture is totally different from most other cultures, and very unique in the history of the world. And so when we're taking data from Westerners, we have to be cautious, and we need more data from other cultures. Because as I say, humans have high variability. Maybe there are people who can get more short-chain fatty acids from fiber than the average Westerner.
And there's very few papers on this, but I found one from South Africa, and they look at autopsies of humans, and they found that some humans have different-shaped colons than other humans, and divided them up into three different kind of morphological types. Here is a short pelvic sigmoid colon, the so-called "classic type", and the long, narrow type.
And different people had different colons. And certain people, like Africans were more likely to have this colon type, and Indians and whites were more likely to have this smaller colon type. And whether or not this has implications for digestion, I don't know. And I think we really need to explore this, because if this colon is so much bigger, what kind of implications does this have?
Can this person get more energy from short-chain fatty acids? Is this person better adapted to a high-fiber diet? And you can see why this sort of research is controversial, because it also has data about different races. But it's very interesting to me. A lot of papers on this subject are not published in English journals at all; you have to read like Czech or something, so it's hard to track down. But it is out there.
What about the evidence that we see in some papers on the Paleolithic Diet, that Paleolithic humans ate 150 grams of fiber a day? I don't know anyone who eats that much fiber, and there's no known modern human culture that eats that much fiber. And most of those estimates are based on [coprolites], and the method for estimating that is quite questionable to me.
We also have to consider the cultural context. There are some good coprolites from hunter-gatherers in the Pecos Basin. But when you look at those coprolites
and the skulls they're associated with, not all Paleolithic or Stone Age or foraging humans are healthy. The Pecos Basin hunter-gatherers have high amounts of tooth decay.
And some anthropologists who study these skeletons say that these are caused by [tooth wear], but this Ota tribesman, he has extensive tooth wear, which is purposeful in this culture. They wear the teeth down to make them look like that, because it's considered beautiful, and they don't have high rates of tooth decay.
If you look at the Pecos Basin skulls, you'll find that they have really high rates of tooth decay. We need to look at whether or not there's impairment of calcium and vitamin D metabolism, and there's a lot of studies that show that really high-fiber diets can impair these. And unfortunately, some of these studies have come about because in places where the macrobiotic diet is popular—the macrobiotic diet, it idolizes high-fiber, particularly brown rice—and in England, in some communities that eat this macrobiotic diet, they're seeing a return of a disease that is associated with developing countries, which is rickets.
And it's infants on macrobiotic diets that have this. And I think there's an upper limit to fiber consumption that's way below some of these so-called Paleolithic accidents. But there's data you can see in some older papers, in particular data from modern hunter-gatherers, foraging people, like this bushman or the Hanza, and they see that these people eat a very high-fiber diet.
But if you look at the later papers, you really have to look at those because they realized that their method for measuring fiber was incorrect. And you can see, this is a very interesting thing. Here's from one of the papers where they're regretting that it was incorrect. And this is inedible material recovered after these Hanza tribe members were eating wild tubers.
They were sending, when they were doing the original fiber assay, they just sent the wild tubers to the lab and they were like, "Estimate the fiber of this," but as you can see here, these people don't eat all the fiber; they're chewing these tubers and spitting out this part of it. So just like you don't eat the tops of your bell peppers, I hope, or the peels of your bananas—although I did meet a raw vegan who was eating banana peels, [laughs]
So cultural evolution is important, and culture isn't even uniquely human. You can see this primate here, this chimpanzee, it's hard to see, but he's taking a leaf and chewing it, and then putting it in this tree that has a hole filled with water and then pulling it out and chewing on it again, and he's doing that to get water.
Humans have even more elaborate techniques. And one of these, of course, is cooking. And we don't know how old cooking is. I mean, you can ask every different anthropologist and they'll give you a different answer. But here we have sago palm starch processing—sego palm is, you know, they're eating a tree. It's not very edible.
Once you cook it, you pound it, and it's quite delicious. I mean it's bland, but it's good to eat; it provides starch for these people, which is very valuable to them. But we also should think about how is food being changed by cooking? It's increasing the food quality, it's increasing the amount of calories you can get from each amount of food.
But it's also really changing some of the nature, the chemical nature of the fibers. Different types of fiber feed different bacteria different ways. So that's very important. And you can look at markers for this. Here's a different kind of culture that a lot of people don’t think about—literal culture, cultured foods.
Fermented foods are universal in nearly every culture. And fermentation increases the bioavailability of protein and several micronutrients. It preserves food. It is a source of short-chain fatty acids. Perhaps it provides us with essential bacteria. Sadly, some fermented foods are in danger of dying out.
And here's an interesting chart—it's comparing the colonic fermentation, this inner fermentation, with exogenous fermentation in fermented foods. And fermented foods can play many of the same roles as colonic fermentation. And perhaps in our evolution as we're shifting towards eating more fermented foods, this was replacing, this exogenous processing was replacing some of the role of colonic fermentation and cooking provides all kinds of different micro-substrates, short chain fatty acids, bacteria, all kinds of metabolites, which also colonic bacteria provide…
They both modulate the system, actually, and there are studies that show fermented food has all kinds of strange effects that you wouldn't expect if it didn't have all these different weird bacteria in it and stuff—to help people lose weight and the way that non-cultured milk would, yogurt is very interesting.
And in terms of metabolites, here's a really interesting one: Butyric acid. It is produced by fiber. Research has focused on just the bulking properties of the fiber. So a lot of early people who wrote about fiber, they were going to Africa and seeing that a lot of different people who ate a very high-fiber diet didn't have the digestive diseases that Americans have.
And they were saying, "No, because it's because fiber is a bulking agent and it increases transit time, keeps toxins from spending a lot of time in the body." But after they were studying more, they found that there were people in Africa who didn't have these digestive disorders who weren't eating a lot of fiber. But what they were eating were other fermentable carbohydrates.
And so now research has shifted away from just fiber as bulking agent, and into seeing fiber more as food for bacteria, whether bad or good. Unfortunately, a lot of research in this area has focused more on fiber being a universal good, when actually it can also feed pathogenic bacteria.
And butyric acid is an interesting byproduct of some of these bacteria. People with colitis, Crohn's Disease, have low amounts of this butyric acid, and butyric acid is very important for modulating inflammation and all kinds of other processes too. They fed these mice the same diet, and the ones that had butyrate didn't gain weight, and the ones that did, that were fed butyrate gained weight. So, pretty interesting.
But you know, when you're thinking of fiber, often your doctors tell you eat more fiber, but different fiber has different effects. And now that we're thinking of fiber more as food for bacteria, you don't need to just think about fiber. And scientists are looking at more of these like resistant starch, for example, and other different complex polysaccharides and carbohydrates. You can see some types of resistant starch are produced by cooking.
Like if you cook potatoes and you leave them in the fridge, then that's resistant starch, and it's very good at producing butyrate. Some of these other fibers aren't so good at making butyrate. A lot of these fibers, a lot of doctors recommend, for example, wheat bran, and that's not even very good at increasing butyrate.
And I'm very sad that there's not a lot of research that is using a lot of these fibers that traditional foraging or horticultural societies eating. A lot of research uses synthetic fibers that's never been eaten before. And they're interesting, but I'd like to see more research on natural fibers.
But also, as humans have developed culture, we have exogenous butyric acid. A lot of people don't know this, but butyric is in the dairy fats and some of the fat under the skin of some animals, particularly cows, goats, sheep. There's a little in elephants too. And there's some in some fermented foods.
Like this is Ogi, it's a pretty delicious fermented food, although it's an acquired taste a bit. But it has some butyric acid. Most Western fermented foods don't have butyric acid because Westerners don't like the taste. If you have tasted skunked beer, you know the taste and you know why we don't like it.
So, it's incrappy traditional foods, you know, foods we don't really like from around the world. But there is one food that you will eat that has butyric acid, and that is butter. The butter is delicious and it has butyric acid. But we don't know whether or not this butyric acid has the same effect as butyric acid produced by colonic fermentation, there's not a lot of research on it.
This presentation's more about hunting hypotheses than presenting research. I'd love to see research on this; maybe I'll do it when I enroll in a program.
But also, not only do humans have all these differences from primates in terms of anatomy and our culture; we have different microbiomes in the gut. And this is a really great study because it looked at the gut biota of wild primates. Most of the other studies have been primates in labs. And you can see, even among these chimpanzees here, these chimpanzees are, some of them are quite geographically isolated from each other.
They have very different branches in the microbiota. They have different gut bacteria. Humans are here. But you can see, we need more data, especially since a lot of these unique cultures are dying out. We should try to collect gut bacteria from them before that, because, so we can get a real accurate reflection of human biodiversity.
And if you think about gut bacteria, it's very complicated because gut bacteria interact with each other, they interact with the metabolites of each other. You have all kinds of diversity among people. Like some people are methane excreters, and some people are not methane excreters. And scientists aren't sure why that is—if that's something that people acquire at a very young age, or if it's something that can be changed.
Methane excreters are quite unfortunate because when they have this bacteria, when it excretes methane, it smells quite bad. So if you're a smelly person, it's probably because you're a methane excreter. But there's just so many questions about why some people are like this and why some people aren't.
And there's so many different sources of gut variation: Cooking and food prep techniques, microbes in food, types of fiber in food, total fiber consumption. Most of us get most of our gut bacteria actually from our mothers, and when we're born, going through the birth canal, we're colonized.
But a lot of us didn't go through the birth canal. I was born by C-section, and C-section babies have different gut microbiota than non-C-section babies, and what is the impact of this? There's some preliminary evidence that C-section babies are more susceptible to certain digestive disorders.
Antibiotic use:antibiotics, if you take them, they can affect your gut microbiota for years. And there's some interactions with genes too. The real question is how plastic is our gut? How much can we change? As adults right now, if we eat differently now, can we really change our gut? Big question.
Here's a really interesting study. This is children in Burkina Faso; this is children in the EU. You can see, you have all these different species, and they differ between these two populations, in different amounts and different species. There are species here that you don't see here. It's interesting because they followed these children when they were breastfeeding, and they had kind of the same gut bacteria when they were breastfeeding.
But when they started eating solid food, their gut bacteria really differentiated. When does this plasticity end? Is it when a child eats its first food? Is that going to really affect the future of that microbiota? Can an adult do this? We suspect they're already there, but in smaller amounts when the infant was breastfeeding.
And then when the solid food was eaten, did it really differentiate based on the food or because of the population seeds planted at birth? We really need to do these studies while different cultures exist because all our multinational corporations are expanding into the developing world, and soon everybody's going to eat the same crappy diet, pretty much, and we won't have this diversity.
And here's the traditional diet of Burkina Faso, a lot of really high-fiber fermented grains. And the environment is very dry. Also, an interesting thing about gut bacteria: Genetic engineering's very controversial, but bacteria have been genetically engineering stuff for ages; it's called horizontal transfer.
A very interesting study looked at Japanese gut bacteria, and they found that some Japanese gut bacteria had species, they had some genes that the gut bacteria had taken from bacteria that live on seaweed, and these bacteria used to digest carbohydrates in seaweed. So these gut bacteria were able to steal these genes and digest these seaweed carbohydrates.
And only Japanese individuals have them, and even breastfed infants have them. So they've probably been in this population for a while. But it really brings it to highlight that our co-evolution with plants, how long have we been doing this? How many genes do we have that are from plant bacteria, for example?
What about the future? Now that we're genetically engineering plants, are we going to acquire some of that bacteria?
And we can use gut bacteria to track human migraation such as h. pylori. H. pylori's considered a pest in the United States because it's associated with some cancers, but actually in Africa, the African strain is not as pathogenic, it's not associated with these things. So these strains are diverse, and you can use their DNA, changes in the DNA to track h. pylori and human colonization of the world.
H. pylori's been with us for 100,000 years, they think. And right now, and most of us don't have it anymore because we tried to eradicate it. What is that doing to us? Did it have positive effects on us that now we've gotten rid of it? There's a lot of variation with it. And also h. pylori has—there's a lot of epigenetic switches that it turns on and off in response to diet.
And a lot of Westerners who do have h. pylori have two strains: They have the non-pathogenic strain and the pathogenic strain. And it's possible that diet can effect an overgrowth in this pathogenic strain. And perhaps the Western diet is taking this h. pylori and turning it into a monster.
But you know, when I'm looking at these different studies, what I said before about Westerners being weird, you really have to question what is normal. There's a hypothesis in anthropology that humans got their first meat and their first high-quality food from scavenging carcasses. It's controversial, though, because most of us don't have the equipment to process rotten meat, although I have met people in the Paleolithic community that are eating rotten meat, and they say they feel fine.
So, you know, that really begs the question if it's normal. And stomach acid, they is genetic variation in stomach acid, but also it's affected by h. pylori—different kinds of h. pylori can affect stomach acid in different ways. Your diet can affect stomach acid. Inflammation. Actually, we associate gastric cancers with the developed world, but actually there are certain types of cancer that are more common in developing nations, such as squamous cell carcinoma, and this is very common in Africa communities that just adopted corn as a staple crop.
And the theory is that, you know, this corn, this omega-6 excess in the diet increases prostaglandin E-2 and it increases inflammation, and that decreases the acidity of the stomach, and leads to heartburn, which is not treated in these developing nations, and then that leads to cancer. There's also an issue I realized studying carrion scavenging, that humans have high transit time variation.
You can feed two people the exact same diet and it'll go through their stomach in different times. And transit time, if you eat carrion, you want a high transit time, and that just varies between humans. An interesting [disease] that I found out about is called [pig bel], and it's people who are in Papua, New Guinea, many who are cultural foraging people, and they eat mainly a very low-protein diet.
They eat primarily tubers, like sweet potatoes and yams. And occasionally they get a pig, and they're very excited about this pig. So they eat it all really quickly. And they get this thing called clostridial necrotizing enteritis. And if I ate this meat, I wouldn't get this, but because they don't eat meat very much, they have low amounts of protease in their gut, so they can't destroy the toxins made by this and can't digest this meat properly.
And it kills some children in these cultures. So, you know, what you eat can affect the different enzymes in your gut too.
And also, the also case of this in a Western individual was a vegetarian who was living in Samoa, and they ate some fish because they were training for a marathon, and they got this disease.
So the point of my talk is that humans are truly unique, and we're not really sure how we got this way, so I'm hunting hypotheses. And within our population diversity is waiting to be discovered. And I'm really worried about loss of biodiversity in cultural adaptations, and what the implications for this are when we're trying to study and trying to flesh out our human history.
When we don't have very much biodiversity to work with, it'll be harder, I think.
And you know, I think the key is balance. I very much admire some of these models that are looking towards the past, and looking at our primate relatives. But also I'm really excited about plant adaptations, new technology and new mutations in human and microbiota DNA.
I think we have to look at both of these things when we're looking at, you know, looking for the best diet for humans. But it also, you know, we often wonder—I have an uncle who's been a vegan for a long time and he's very healthy, and he says, "I've been a vegan for 30 years," and I was a vegan for only a short time and I felt awful.
And we're related to each other, but there's probably some difference in our microbiota or our genes that make him better adapted to this diet than I was. So it gives a new viewpoint on why do some people do better on one diet or another?
So I'd like to thank Ralph Holloway, Chris Masterjohn, Stephan Guyenet and John Speth. They've really helped out. So thank you.
Male Voice: So you would say that your main point is that the diversity of humans is under-appreciated and the difference between people is under-appreciated? Is that fair?
Melissa: Yeah. That people are very different from each other, and will thrive on different diets.
Male Voice: I was struck by a thing you said about most of the gut bacteria comes from your mother when you're born. I was wondering what the implications are for celiac, whether that can spread celiac disease.
Melissa: Yeah. I think a lot of celiac research has focused maybe too much on our own genome, what we share, that there's genes that make us susceptible to celiac. But there's also probably gut bacteria that make us susceptible to celiac, and genes within our gut bacteria. So I think that'll be a future avenue of research in the future.
Male Voice: I was wondering about [unintelligible] research on doctor [unintelligible] work? He looked at the microbiota and found that people have different communities, three communities of microbiota.
Melissa: Oh yeah, I saw that. But they're not sure what the implications of that are. They couldn't connect it with anything, like obesity or any diseases yet. But it's very interesting. They found that some people have very specific—that they divide Westerners, at least, into three specific groups of dominant bacterias. And it was fascinating, but I'm really excited to see what that doctor comes up with.
A poor evolutionary nutrition narraive posits that because we didn't have X food in the paleolithic, we are maladapted to it. I think Mat Lalonde covered issues with this nicely at AHS and in the latest Paleo Solution podcast.
John Hawks, a biological anthropologist at the University of Wisconsin-Madison, notes that many HLA genes pre-date humans' split from Neanderthals and Denisovans, and that the differences may have arisen by chance as the groups evolved.
Hawks, too, has been digging into the archaic genomes, and his team has already discovered that Neanderthals and Denisovans lack certain forms of genes that may help modern humans to fend off epidemic diseases, such as measles. This is hardly surprising: the low population density of hunter-gatherers meant that epidemics were unlikely, so they probably would not have benefited from these immune genes.
But Hawks's team is now using the find to test whether the defensive genes are linked to autoimmune diseases. In September, Hawks and his colleague Aaron Sams are scheduled to present data at a meeting of the European Society for the Study of Human Evolution in Leipzig, Germany, showing that the Denisovans lacked nearly all of the gene variants linked to coeliac disease, a gut autoimmune disorder present in modern humans. Hawks suspects that the variants may actually be in the same genes that are linked to epidemic resistance — if they are, further study could reveal how recently such autoimmune diseases arose in humans.
Haha, it would be funny if an adaptation to civilization (diseases worsened by high population density), would also turn out to be a maladaptation as civilization progressed.
Some of my readers might be interested in The Atlantic's debate on "alternative medicine." Reading it, what amused me is that opponents of alternative medicine accuse it of not being "evidence-based." Unfortunately our "normal medicine" isn't really evidence-based either. What doctors and hospitals do often seems more about the status quo than science. That explains why my sister (a biologist) and I are not exactly our doctor's favorite patients. We don't accept treatments based on outdated science, particularly when they have harmful side effects.
For example, the idea that GERD is a disease of acid burning the esophagus is several years outdated, but doctors continue to hand out medicine based on that theory (proton-pump inhibitors) like it's Halloween candy, despite a growing body of evidence that it causes immune dysfunction and bacterial overgrowth!
The list really could go on and on, from unwillingness to adopt life-saving safety practices to the handing out of antibiotics to children for every little thing (even illnesses obviously caused by viruses!) to the use of questionable materials for hip-replacements just because they are "new."
Another example showed up in my RSS reader today: Keeping Mother and Baby Together – It’s Best for Mother, Baby, and Breastfeeding. I suggest you read that post, as it has great information. Basically, in our species, the time immediately after birth is critical. Direct skin to skin contact between mother and baby is important for establishing breast feeding, bonding, and regulating the baby's physical health. That's how our species evolved, it's the infant's natural ecology. This isn't about just doing what our ancestors did; science has confirmed that these practices have important functions. Despite that, hospitals often fight this practice and a woman who wants to simply do what is appropriate for her as a Homo sapians must exert an effort to convince the hospital staff, find a sympathetic birthing center, or arrange for a home birth.
Interestingly, NICU's (new born intensive care units) have been the first to adopt this practice. For babies on the edge, everything counts, but it's something all babies deserve.