This blog is about the intersection between evolutionary biology and food. But also about practical applications, sustainable agriculture, and general tasty things.
Whenever an article about the paleo diet is published in a major newspaper, at least one commenter expresses dismay that paleo dieters don't realize that humans are adapted to grains and milk. That's a misconception on several levels. First of all, plenty of us are educated enough to know that genetic adaptations can occur rapidly. I remember in high school when I first read The Beak of The Finch, which is about the finches in the Galapagos islands and how their populations genetically respond rapidly to changes in the environment. It takes down the myth that evolution is slow and can't be observed.
In that case, why are we still talking about what our ancestors eat as if it matters? Well, so far the evidence is that some adaptations have occurred in some populations response to neolithic food. Genetic evidence shows that most of the population in modern societies is descended from agriculturalists who had been farming for several thousand years. Clearly, our ancestors were very much able to survive on diets of grains and dairy.
I was just reading this scientific paper, Demeter's Legacy, which is free online and a fascinating read. Yes, there are two major genetic adaptations in agriculturalist populations. One improves the digestion of starch and the other of dairy. Great, we can eat these foods and reproduce. Yay, but it doesn't mean that we are completely adapted to them. There are plenty of foods that are digestible for everyday needs, but damaging in the long term. It's up to us to do the research and figure out if foods are really worth it. I ate bread for most of my life and felt OK, but life for me is not just about surviving, but about thriving. It's important to remember that even though adaptations have occurred, the vast majority of our genes were forged before agriculture.
And for people descended from more recent hunter-gatherers, neolithic foods are even more devastating.
I created a list that I am currently still adding foods to which outlines some pros and cons of various foods from the paleo viewpoint. I think foods should be judged on their merits and there is no "one true" paleo diet...there can't be, since last time I checked I couldn't get wild antelope at the grocery store. It's about learning from the wisdom of the past and choosing food based on those principles, not reenactment.
Really easy to find at your local garden shop or next to your sofa!
I don't understand why so many paleo dieters neglect to consume cycads. They have been a part of our diet since the stone age and numerous hunter-gatherer tribes enjoy them. I hear that their starch goes really well in a puree of herbs with salmon. Making them is REALLY simple too! First you take the pith from the trunk, roots, and seeds and grind them into a coarse flour in your Vitamix. Then you soak it for five days and wash it out carefully several times to remove toxic chemicals. Finally, bake it on some hot rocks or ferment for several days. If tribal people in the jungle can do it, you can too.
Scientists don't recommend eating this, as some nerve toxin and other assorted natural chemicals could remain, but we paleo dieters know that it's a perfectly good food that people have eaten for hundreds of thousands of years! In fact, it's so valuable to hunter-gatherers that women will spend hours and hours preparing it.
Unlike potatoes, which they did not eat and therefore they are really bad. I can't find any studies that show that potatoes cause arthiritis or anything, but if Grok didn't eat it, then it doesn't belong. Who knows what it could do it you?
Next time you are craving potatos, reach for your nearest house plants and start processing! Stone age foods are always good and neolithic foods are always bad!
*just kidding. There is nothing wrong with modeling your diet on evolutionary principles that posit that the stone age was when we were eating food we evolved to eat, but it's fairly shallow to think that everything that is neolithic is bad. Almost ALL our food is technically neolithic. We should evaluate each food scientifically in light of our evolution.
Lately I've been reading Ancient Bodies, Modern Lives. The book is already dog-eared because there is so much interesting information in there. While some people have said that the paleo diet is "unwomanly" this book really makes it clear that women bear the brunt of the consequences of the inappropriate diets most humans eat these days. It also is a great reminder that diet isn't everything and aspects of human lifestyle that may seem trivial can have a huge impact.
A couple of months ago I read The Continuum Concept and I've been meaning to blog about it. This book was written the year I was BORN, but has some of the foundations of evolutionary medicine. Jean Liedloff believed that the human body expects certain things because of our evolutionary past and that there are consequences for subverting this. While living with indigenous people in the Amazon, she noticed how differently they treated their children compared to Western women. Unfortunately, she was not trained as a scientist or an anthropologist, so while she was able to understand that this was important and had huge consequences, much of her book is psychoanalytic speculation.
Ancient Bodies, Modern Lives is written by biological anthropologist Wenda Travathan. It's definitely an academic book, but it's very readable and clear that Wenda has been involved in a movement to allow women to give birth in a way more appropriate for our species. It's pretty much everything I wanted in The Continuum Concept and brings the evolutionary paradigm further by delving into biology.
The natural birth movement is often associated with unscientific sentiment, but after reading these two books it's clear that modern birthing and child rearing methods are a huge source of misery for women, men, and children. Some of the advice in these books is eminently practical and most of it shatters childbearing preconceptions I never even thought to question.
Obviously a baby in the paleolithic era was born vaginally. Lots of women think "thank god we live in the modern era, because I/my mom/many women would have died in other eras because they didn't have C-sections." But what if the C-sections aren't a boon of the modern era, but a consequence of modern life? Coincidentally I have a copy of The Vitamin D Solution and previewing it I turned to a page that said that "In 2008, Anne Merewood and D. Howard Bauchner and my team reported a landmark study indicating that women who had low 25-vitamin D levels were more likely to have a C-section....we concluded that a woman with low vitamin D levels is four times more likely to deliver by C-section..."
A baby in the paleolithic was also not placed in a crib to sleep alone. That might seem trivial, but an alone baby in the paleolithic was a dead baby. Wenda presents evidence that the Western ideal of having a baby sleep alone through the night is unrealistic and perhaps even harmful to both the baby and its parents.
A paleolithic baby was also breastfed. I think scientific research has made it obvious that any formula is inferior to the real thing, a testament to humanity's folly at playing god in issues of nutrition.
Then there is the obvious fact that women my age in the paleolithic were having babies, whereas I and most other women my age are actively trying to delay doing so. What are the consequences of delaying childbearing? Of hormonal birth control? These are important questions to consider.
And I will be considering them in the next posts.
Feeding off my post about what our bodies expect, I thought I'd take it to another dimension. It's a total myth that since humans evolved in the seasonless equator, seasons don't matter. They do have seasons at the equator, they are just different from what we think of as seasons. As discussed in Seasonality and Human Evolution, the seasons we dealt with for most of our evolution were just two: wet and dry.
Neanderthals show physical adaptation to cold climates, but all humans have a fairly "tropical" morphology. That doesn't mean that the northern four seasons are unimportant, especially since the duality is still present and there is the possibility of smaller, but still important, genetic changes. Particularly significant is that genes for energy metabolism show climactic variation.
Either way, no matter where your ancestors came from, eating the same diet all year is probably not natural. Eating with the seasons enables you to adapt better to your environment and to reap the benefits of two types of diets. Paleo dieters already mimic the feast and famine of early life with intermittent fasting, but eating seasonally allows you to also mimic another important duality.
Right now many of my locavore friends are complaining about the lack of food selection in this late winter season. Most of them are vegetarians or eat very little meat and are having to buy imported foods to get by. There are a few stalwarts surviving mostly on various roots and tubers, but that doesn't seem very delicious or nourishing to me.
While they eat their potato beet rutabaga pie, I'm eating luscious chicken confit, beef stew, lamb shanks with celeriac mash, and wild boar with garlic kale. Local doesn't feel forced to me anymore, it's easy and natural.
It took me a long time to get to this point. When I was raw vegan I savored bananas. melons, and salads in the dead of December. Back then, even a teensy draft set me a shivering. I was completely miserable. My diet was full of "live" foods, but I felt dead. No matter how many layers of sweaters and blankets I put on, I was freezing. A walk along the frigid harbors of Stockholm was impossible.
This winter I have eaten ample amounts of fat and thyroid-supporting foods like seaweed. I feel perfectly warm and no longer need five gazillion wool blankets to get to sleep. The cold north wind blowing off the Hudson river doesn't faze me. I hardly feel deprived...I LOVE the food I'm eating and I feel nourished. The best thing is that I no longer crave sweet foods like I used to. I chalk it up to adequate fat.
December used to be for peppermint ice cream, February for gallons of heart shaped candies, and in early March I started my Cadbury Cream Egg binge. Last night I passed the Cream Eggs at the store and was briefly filled with nostalgia....but then I remembered how insipid they taste and how much better my duck confit tasted.
I hesitate to recommend TS Wiley's Lights Out: Sugar, Sleep, and Survival, because I feel it's a little lacking in scientific rigor, but it does have some important ideas. Wiley believes eating sugar in the winter keeps your body in a constant state of summer, where you need to eat as much as possible to pile on pounds for a long winter. Her prescription is to eat no sugar in the winter, but as much as you want in the summer. A similar idea may apply to omega fatty acids-: omega-3s are a summer fat and omega-6s a winter fat according to Susan Allport (hat tip to Matt Metzgar). That makes so much sense to me. The omega-3s in meat come primarily from fresh grass and animals lay down omega-6 rich fat stores for the winter. Omega-3s in large amounts can also have an immunosuppressive effect, which could be maladaptive for a long tough winter. Another area of concern that seems to be seasonal for me is the acid-base balance, which is slightly controversial, but regardless, my diet is net acid in the winter and net alkaline in the summer.
We can't forget the obvious thing: Vitamin D from sunlight, which probably accounts for the seasonality of some of the illnesses in the aforementioned book. Vitamin D is important in the winter, but it's even more important to go outside and get some sunlight in the summer when your body is expecting it.
Despite the richness of my diet and exercising much less in the winter, I have no gained any weight. In the summer I expect that my desire for fat will wane and I'll fully enjoy the bounty of fruit, herbs, and fish at the farmer's market. By autumn, as the days get colder, I will yearn once again for richer foods.
My ancestors have lived in the North for a long time, perhaps this is what my body expects. Either way, eating seasonally has allowed me to feel better and to truly enjoy local food in a way I never did when I forced myself to eat low on the food chain.
When I was a child I went to "marine biology" camp at a marine animal theme park. I remember being very enthusiastic about working with dolphins and seals. That enthusiasm was promptly crushed when I got to see the tiny concrete cages where they spent most of their lives. The were painted that garnish teal color that swimming pools tend to be painted and reeked of disinfectants. They fed them the cheapest rancid throw-away fish, a world away from their rich and diverse diets in the wild.
I thought about that when I heard about the killer whale at Sea World that drowned a trainer. Killer whales in captivity live in environments completely inappropriate for their species' evolutionary heritage. At least most zoos try to make things like in the wild, but marine parks are all about concrete. Instead of eating seals and salmon, they eat whatever fish is cheapest on the market. Instead of living in pods, they are sometimes kept alone. Of course they suffer from reduced lifespan and bizarre pathologies like dorsal fin collapse.
Author Erich Hoyt said:
As I reported in The Performing Orca and also in some detail in Orca: The Whale Called Killer, trainers have noted that orcas start to get bored and go a bit crazy after a few years in captivity. You must imagine a highly intelligent social mammal and a big predator normally traveling 100 kms or more a day, then taken from its family, stripped of its ability to socialize normally, to hunt and to travel. What it has left is its relationship to the trainer, but how long can that really keep them interested?
Substitute a few words and that could be about Homo Sapiens. It's interesting that despite the immense power and predatory nature of killer whales, they don't prey on us in the wild. They have even been known to cooperate with humans in the hunt. The killer whales of Eden that were documented to cooperate with humans might be the tip of the iceberg in that relationship, as it might have been present in other cultures and died out before it was documented. Perhaps killer whales recognize us as kin: high intelligent seafaring top level predators.
Some of you might think "Why is a woman who has eaten whale talking about this?" Hunting is part of our evolutionary heritage and benefits us physically and emotionally. Keeping animals in concrete tanks is not. We can and should provide evolutionarily appropriate environments for both animals and humans. It benefits the health of all involved.
If Sea World provided larger more natural tanks for its animals and a diet of penguins, seals, shark livers, whale tongues, and other nutritious traditional orca foods...I might go there, but I doubt that will happen anytime soon.
The gate of knowledge is closed!
Oh how ungrateful I was back then when I was enrolled in a big university. I didn't realize how annoying it would be to not have access to a large academic library. Sciencedirect now asks me to pay five gazillion dollars for the studies I want to read. It almost makes me want to enroll in school again.
I live in freaking NYC, but the library here doesn't have the richness of that library in the middle of Illinois.
When I did have access to the wonderful online research databases, I remember seeing that some misguided nutritionists and anthropologists cited papers by S. Boyd Eaton when they tried to say the paleolithic diet was plant-based and low-fat. So it's nice to see Eaton himself in this recent article about the paleolithic diet in Macleans eat his hat:
He says he had failed to consider the contribution of non-muscle meat like brain and fat depots, and thus underestimated the amount of fat we need. “It makes me feel stupid!”
Oops. Also on display is tehstupid
Konnor still thinks that was the right call, and believes his original concerns about fat were prudent. “You can’t just go to the supermarket and buy meat loaded with fat and say you’re doing the Paleolithic diet. You’re not.”
Ugh, such an annoying misconception perpetuated by restaurants that serve miserable cuts of miserable game for miserable prices. Yeah, that wild boar tenderloin roast at terrible overpriced restaurant is lean because the company that sold it is feeding the public's desire for "lean" healthy game. Any real hunter can tell that that game varies in fat content by species and season. Some game is very very fatty! And the cuts served at Green Meadows Fancy Golf Course Grill, typically lean cuts, are not representative of the real richness of game. This Hazda article speaks more to traditional consumption
Bones are smashed with rocks and the marrow sucked out. Grease is rubbed on the skin as a sort of moisturizer. No one speaks a word, but the smacking of lips and gnashing of teeth is almost comically loud.
Speaking of bones, I just finished reading the excellent cookbook Bones, by Jennifer McLagan. A full post on this excellent book is due, as bones are absolutely essential for a successful paleo diet, providing ample amounts of fat, calcium, and other important nutrients.
Also, what's the deal with lacto paleo? I must say I'm not a fan of this trend or term. A paleo diet with dairy is not a paleo diet, it's a nomadic pastoralist diet. Such pastoralists are pretty healthy, but they are not representative of stone agers. There is absolutely no convincing evidence that dairy is paleo. That doesn't mean it's bad, but it does lead to some dilution of the paleo terminology.
Also annoying is this NY Times article about some who argue that depression is somehow an evolutionary adaptation. In my opinion it's like arguing that heart disease is an evolutionary adaptation. I think it's fairly clear that depression is a disease of civilization caused by living inappropriately to our evolutionary heritage whether it's working inside all day staring at a glowing rectangle or not getting enough omega-3 fatty acids. Unfortunately this viewpoint is not in the article. The opposing view is that it's a hopeless disorder that can only be treated with modern drugs.
I thought about that when reading the graphic novel bio of logician Bertrand Russell. He is devastated by the schizophrenia that seems to be an inevitable part of his bloodline. But there is increasing evidence that omega-3 fatty acids play a role. That this type of research is being done in the age of drug fixes is very hopeful and I would bet that scientists will eventually find even more nutritional factors that govern mental illness.
Then I often ask where, as a society, did we stray from that lifestyle of whole vegetables, tubers, grains, fruits and legumes because I am confident that evidence shows that we evolved using such foods, which comprised at least 95-98% of our diet. Before the 1850s, very few people ate animal based foods. The royalty did and their paintings and pictures and gout show it.
It's amazing...he's a doctor....doesn't he have access to Sciencedirect or any other scientific databases? There is ample and irrefutable evidence that humans have been eating meat and lots of it for a very very long time. Certainly he has access to Google Scholar. Hint: plug in "meat" + "human evolution" or "meat" + "isotope studies." If anything, Colin is a sad example of how increased specialization in science furthers ignorance. There is really no good excuse for a doctor to not draw on the vast wealth of anthropological research, especially if he is going to make claims like that.
The pharaohs, who suffered numerous health problems including gout and heart disease, were also big consumers of grain and alcohol.
Gene Expression has a facinating post on the transition from foraging to agriculture and how it affected human welfare. The graph Razib drew is interesting:
Thinking about it in a dietary context, I added a green line. Of course it is a rough approxamation. It would certainly be interesting to do a really well-researched version of this graph taking into account the archeological evidence, but this graph does show some important things. We in the modern era (well, some of us in 1st world countries at least) are lucky in many ways, as mortality is pretty much lower than its ever been. We don't have to worry very much about ourselves and our children getting felled by a random infection or being eaten by wild animals. But the so-called diseases of civilization really keep us from living up to our full genetic potential.
Where on this timeline do you want to eat? There are actually several good choices that seem to allow one to avoid diseases of civilization.
I suppose it all depends on that dotted line from this graph on Demeter's Legacy. Certainly, there are both cultural (soaking and fermenting grains) and genetic adaptations that make agricultural food less harmful to humans. Eliminating the basic poisons of the Industrial Revolution like refined sugars and grains is often enough to restore health. I suppose it is up to you as an individual to decide if you are experiencing maladaptation from an agricultural diet. The cause of maladaption could be genetic, but it also could be that the illnesses developed on an inappropriate diet require going back to the basics. I feel that is certainly the case for me.
This paper explores the diets of gorillas and uses it to recommend a diet for humans low in fat and high in dietary fiber. This is a common mistake. Dozens of vegetarian groups say that because the great apes are vegetarians (which they aren't...but animal food intake is fairly low) that humans are also naturally vegetarians. The most extreme groups say we should eat only fruit because, as primates, we thrive on sugar.
But read the paper carefully. The gorilla diet is very very high in fiber, but that fiber is getting converted into free fatty acids. This conversion is vital for gorillas, providing them with 57% of their calories. That leaves 15.8% of calories from carbohydrate, making the gorilla a defacto low carber! Humans claiming to emulate ape diets by eating lots of fruit aren't able to get the same nutrition. Fruits that are palatable to humans are much higher in sugar and lower in fiber than what the great apes eat. Furthermore, the human colon is tiny in comparison to great ape colons, so even if we did eat high-fiber fruit we wouldn't be able to process very much of it into free fatty acids.
Here is why a fruity "ape" diet is bird-brained:
What's also true is that E. coli only showed up so prolifically in the guts of cows since they've been fed corn in the last 50 years or so. A starchy food the grass-eaters didn't evolve to consume, corn produces an acidic mess in their stomachs that E. coli bacteria apparently loves.
I just realized today that you could totally rewrite that sentence and it would still be true.
What's also true is that E. coli only showed up so prolifically in the guts of human since they've been fed so much corn in the last 50 years or so. A starchy food the meat and vegetable eaters didn't evolve to consume, corn produces an acidicmess in their stomachs that E. coli bacteria apparently loves.
It's not just acidic stomachs of cattle that E. Coli love, it's acidic stomachs of humans too. The amount of food poisoning cases attributed to pathogens that aren't big fans of acid, like salmonella, has dropped. Well, except for in the other extreme end up acidity, which is the growing population treated with drugs like Proton Pump Inhibitors that reduce acid too much, thus leaving them susceptible to other nasty types of food poisoning.
All that is clear is that in the US our stomachs are a mess. We should make an effort to get them back to normal by elimating both grains and acid-reducing drugs.