This blog is about the intersection between evolutionary biology and food. But also about practical applications, sustainable agriculture, and general tasty things.
In the debate surrounding the NYC ban on large soft drinks earlier this year, the argument came up that we had to regulate them because liquid calories are evolutionarily novel and inappropriate for our species to consume because we cannot consume them moderately and their metabolism is harmful to our bodies. At the time I had already started reading Patrick McGovern's Uncorking the Past, which looks at human history through the very lens of liquid carbohydrates.
Not soda, something a bit more delicious and perhaps more enticing. I'm talking about alcoholic drinks. It was in the form of such a drink that I first encountered McGovern's work. I was not pulling in very much money at the time and my indulgence in luxury food and drink primarily came from volunteering at ritzy galas. After one long night, I was delighted to find a vendor had left quite a lot of good beer behind. One of them was Dogfish Head's Midas Touch. With a musky wine-like flavor, it was clear this was not a normal beer.
The idea for the beer came from a golden residue found in a tomb where either the real King Midas or his father was buried around 700 B.C. Archeologist Patrick McGovern had analyzed this residue, teasing out the various ingredients using infrared spectrometry, gas and liquid chromatography and mass spectrometry. Grapes, honey, and barley had were the ingredients of this ancient beverage. Together with the brewers at renowned microbrewery Dogfish Head, McGovern set out to recreate something with these elements for the modern palette. The result was well-received and the first of the Ancient Ales series went to market.
McGovern is the "Scientific Director of the Biomolecular Archeology Laboratory for Cuisine, Fermented Beverages, and Health at the University of Pennsylvania Museum in Philadelphia." He primarily works at analyzing ancient pottery residues to figure out what exactly our ancestors were imbibing in. And for fun he recreates some of these beverages for modern people to enjoy.
Uncorking the Past says "No containers have yet been recovered from the Palaeolithic period, not even one made from stone. Objects made of wood, grass, leather, and gourds have disintegrated and disappeared." Since it came out, several Paleolithic pottery specimens have been described, mainly from China. Earlier this year, one set of shards was dated to 20,000 years ago. It would not be surprising to me if much earlier pottery is discovered in Africa. Evidence for the earliest food grind stones used to process seeds has been dated to 105,000 years ago. It is possible though that humans in that region were using other containers for liquid such as skins or gourds, but pottery would have been a major advance useful for extracting fat from bones, detoxifying and cooking starches, and creating fermented drinks.
Such drinks would have not been terribly novel even then. As McGovern points out, our evolutionary line is frugivorous in origin, having inhabited warm tropical climates where "as the fruit matured, it would have fermented on the tree, bush, and vine. Fruits with broken skins, oozing liquid, would have been attacked by yeast and the sugars converted into alcohol. Such a fruit slurry can reach an alcohol content of 5 percent or more." Many cases of wild animals getting drunk on ripe fruit have been documented.
Malaysian tree shrews, subsist mainly on fermented palm nectar that is up to 3.8% alcohol. The researchers concluded:
The pentailed treeshrew is considered a living model for extinct mammals representing the stock from which all extinct and living treeshrews and primates radiated. Therefore, we hypothesize that moderate to high alcohol intake was present early on in the evolution of these closely related lineages.
Wherever primates live, they seem drawn to sugars. Chimpanzees use tools to gather honey in Africa. Hominids there have been adapt at exploiting honey for a very long time, devising elaborate gathering systems to thwart the aggressiveness of native bees. Surveys of foraging tribal peoples like the Hadza and Pygmies have revealed that honey is the food they most prefer. It can also be used to make alcohol:
Many African peoples have been drinking some variation of a fermented honey beverage for a very long time throughout the continent. The strongest versions have been reported from the Rift Valley, where added fruit (e.g., of the sausage tree, Kigellia africana, and tamarind), with additional yeast to spur an extended fermentation, boosted the alcohol concentration. Sub-Saharan Africa is a honey-eater's and mead-drinker's paradise.
It's not just shrews that enjoy palm wine either. Evidence for human exploitation of palm goes back 18,000 years in Africa:
The most important species for making palm wine are the oil palm (Elaeis guineensis), the ron or Palmyra palm (Borassus aethiopum), and the raphia palm (Raphia vinifera), which are concentrated along the humid east and west coasts as well as in the dense jungles of the interior...A healthy tree can produce nine or ten liters a day and about 750 liters over half a year...Within two hours, palm wine ferments to about a 4 percent alcohol content; give it a day, and the alcohol level goes up to 7 or 8 percent
Now back to those food grind stones. The papers that describe them typically talk as if they were used to make the world's crappiest bread out of miserable wild grains. Other grind stones had more obvious uses- they ground pigments for decoration. Why not smear your face with makeup and go out and party? What if the "food" grind stones were really used for making alcoholic drinks? What if people domesticated grains mainly to use in the creation of alcoholic drinks? Seems like more of an incentive than making bitter flat fibrous bread disks.
It would also explain why the wild relatives of so many grains are mystifying. Looking at teosinte, the wild ancestor of corn, it's kind of baffling why humans would have bothered with the plant at all:
A series of careful DNA studies identified teosinte (genus Tripsacum) as the wild ancestor of maize. This mountain grass grows in the Rio Balsas drainage of southwestern Mexico. One cannot imagine a less inspiring plant to domesticate. The ears of this primitive corn, which are barely three centimeters long and contain only five to twelve kernels, are trapped in a tough casing. Even if you manage to free up the kernels, their nutrient value is essentially nil.
The mystery might be solved by quids, chewed and spit out fibrous plant material. This might sound gross, but chewing of place materials and spitting it into a container is an alcohol-making process that has been documented around the world. It seems very likely that the stalks of teosinte were used for this purpose.
The human mouth converts the starch to more easily fermentable sugar using amylyse. Some mouths are better at this than others. Starch consuming peoples typically have a greater amylyse copy numbers, though all humans have a greater copy number than primates like chimpanzees and booboos. "Higher AMY copy numbers and protein levels probably improve the digestion of starchy foods and may buffer against the fitness-reducing effects of intestinal disease." Stephan Guyenet and I have discussed how the copy number thing is interesting because salivary amylyse, even at high copy numbers, contributes very little to digestion of starch relative to pancreatic amylase. What is the increased copy number for salivary amylyse for then? Perhaps for chewing starches like rice and corn to make delicious alcoholic beverages.
Chicha made with saliva remains an important part of the diet of many South American tribes, and a woman's ability to make it is important for her husband's social status. It is rude to refuse it, as this account written up in Salon describes
Patton maintains that the bulk of an Achuar’s daily calories do not come from meat. They come from chicha, a mildly alcoholic, vaguely nutritious, watered-down manioc mash. Achuar men drink up to four gallons a day.Isaac’s wife and mother are in constant motion, serving bowls of chicha to the 10 or so guests. Chicha is the backbone of Achuar society. As with the ankle bone and the knee bone, you feel an unalterable pressure to accept. Chicha is the holy communion, the Manischewitz, the kava-kava of Achuar life. It’s present at every ceremony, every visit, every meal. An Achuar woman’s desirability rests in no small part on her skill at chicha brewing and serving.
Given the amount of calories and nutrients such beverages can provide, it amazes me that many ethnographical and anthropological surveys seem to ignore or downplay their presence, as if they were just mere recreation.
Corn chicha, widely consumed in South America, could not only explain the domestication of teosinte, but it could also account for the fact that isotope studies during the time of corn's domestication don't seem to show people got their protein from corn:
Some very interesting results emerged when human bones from sites throughout the New World were examined. Because maize had been domesticated by about 6ooo B.P., one would have expected to see a specific carbon-isotope composition that reflected the increased consumption of maize, but it was strangely missing. Some scientists have proposed an explanation for this anomaly. Because the analyses measured only the collagen in bone, its main proteinaceous connective tissue, they were biased toward detecting high-protein foods. Solid foods made from maize, including gruel or bread (e.g., tortillas), fit this requirement, but not fermented beverages like maize chicha, largely composed of sugar and water. Consequently, if people between 6ooo and 3000 B.P. were consuming their maize as chicha, very little protein would have been incorporated into the collagen of their bones. The researchers speculated that humans began using maize as a solid food only after its ear had been substantially enlarged by selective breeding, around 3000 B.P. After this point, the carbon isotope compositions of bones dramatically changed.
Interestingly, going further north, the Native Americans there didn't seem to have any alcoholic beverages, or if they did, they had been spread from the South. Charle's Mann's 1491 discusses the hypothesis that the North and Southern Native Peoples were peopled differently, South America being populated by a sea-faring coastal society, rather than from Beringia up North. McGovern describes the culture of the coastal peoples, who consumed a tantalizing array of berries, fish, mollusks, wild tubers, mastodon meat and fat (they processed enough fat that it congealed on the floor, which my sister's roommate reenacted recently by pouring some bacon grease directly down the drain), bulrushes, and seaweed. It is theorized that the cold snap of the Younger Dryas around 13,000 BC may have forced them to rely more and more on underground tubers, spurring on the domestication of the potato.
However, the Siberians, like the North Americans, do not have alcoholic beverages (that we know of at least), relying on other resources for a buzz:
In place of any alcoholic beverage, the Siberian peoples engaged in shamanistic practices based on the hallucinogenic fly agaric mushroom (Amanita muscaria). When European explorers finally braved the frigid tundra of Siberia, beginning in the mid-seventeenth century, they recorded how the shaman often dressed in a deer costume with antlers, like the Palaeolithic creature depicted in Les Trois Freres cave (see chapter i). After consuming the mushroom, he would beat on a large drum, whose monotonous repetition reinforced the effects of the active hallucinogenic compounds (ibotenic acid and muscimole) and took him into the ancestral dreamtime.
Northern peoples in the Americas also smoked tobacco. Meanwhile, people in the Southern parts North America certainly did imbibe in alcohol. The Pima who are so infamous in nutritional circles consumed a sweet cactus wine. The health effects of another regional beverage, Pulque, which is made by fermenting agave sap, have been explored a bit. It was found that among highland tribes that consume it, it accounts for much of the iron and Vitamin C consumption in pregnant women. Pregnant women who consume too much or none are more likely to have low-BMI and reduced mental performance infants. Consumption of pulque might also increase the bioavailability of vitamins in other traditional foods.
The use of agave in fermented beverages should be considered when looking at data from that region that suggests a high fiber consumption from these plants, particularly given the presence of quids and the fact that these fermented beverages could enhance digestion of fructooligosaccharides in these plants. I've seen such papers conclude that this means that humans in these regions ate absurd amounts of fiber and we should emulate them. What is more likely: that anatomically moderns humans were eating 255 grams of fiber a day from plants like agave, well above what any known living culture consumes, or that they were making something a bit like tequila?
It is possible that such drinks have been under emphasized because of very real issues of alcoholism that plague many modern indigenous peoples. However, most of these traditional alcoholic beverages are not like the modern alcohol that is abused. Indigenous beverages are typically 3-6% alcohol, seasonal and contain many nutrients and phytochemicals, which are biologically active plant chemicals. McGovern's lab has been working on exploring the medicinal properties of many of these phytochemicals.
McGovern describes how many of the early beverages in the Middle East, ancestors of our modern wines and beers, contained potent medicinals. Early grape wines, for example, often contained tree resins:
Tree resins have a long and noble history of use by humans, extending back into Palaeolithic times. They could be used as glues and were perhaps even chewed to give pain relief, as suggested by lumps of birch resin with tooth marks that were found in a Neolithic Swiss lake dwelling...Resinated wines were greatly appreciated in antiquity, as we have come to see in analyzing wines from all over the Middle East, extending from the Neolithic down to the Byzantine period. Although some wine drinkers today turn up their noses at a resinated wine, now made only in Greece as retsina, the technique is analogous to ageing in oak. The result can actually be quite appealing: the Gaia Estate's Ritinitis has a mildly citrusy flavor, achieved by adding a very slight touch of Aleppo pine resin to a Greek grape variety. Even the Romans added resins such as pine, cedar, terebinth (known as the "queen of resins"), frankincense, and myrrh to all their wine except extremely fine vintages. According to Pliny the Elder, who devoted a good part of book 14 of his Natural History to resinated wines, myrrh-laced wine was considered the best and most expensive.
It is a powerful reminder to consider ancient diets holistically, that things were not just consumed for their nutritive value, but for recreational, medicinal, and religious purposes. And possibly some of these substances were "unwise" traditions and may account for some of the diseases found in mummies and skeletal remains if people drank too much or adulterated their beverages with carcinogens and other poisons. Even today, adaptation to alcohol seems uneven and imperfect in humans, as many Asians who experience Alcohol Flush Reaction will attest. Distilled high-alcohol spirits are also very much an evolutionary novelty. As someone with alcoholism running in the family, I very much understand that consumption of these kinds of alcohol can be difficult for certain people to moderate with terrible, even deadly consequences.
I think renewed study and emphasis on fermented alcoholic beverages in human evolution will provide much insight into human adaptations to food and the development of domesticated crops. Even with the knowledge we have now, I think it's wholly inappropriate to describe liquid carbohydrates as evolutionarily novel. Soda is novel in that it is a liquid carbohydrate devoid of any of the nutrients or phytochemicals in indigenous beverages, but mainly we need to look to modern science and biochemistry to tell us what effect soda has on the body and mind.
It's also fascinating to see some of these ancient beverages recreated and revived. I've since tasted several of McGovern's collaborations with Dogfish Head, such as Chateau Jiahu, which is made of rice, honey, and fruit recipe gleaned from 9000 year old Chinese pottery. I've also enjoyed some of the more modern spit-free chicha at several Peruvian restaurants and being a lightweight, I appreciate that it's pretty low in alcohol and also very tasty. There has also been renewed interest in home brewing ancient herbal ales. You can do it yourself with the book Sacred & Herbal Healing Beers. There are also some herbal beers on the market. I've enjoyed William Brother's spruce, seaweed, and heather beers. Unfortunately, none of these beers are gluten-free, which is slightly disappointing since the original Jiahu pottery probably did not contain barley.
I enjoyed Uncorking the Past, but it does read a bit like a textbook at times, which is why it took me so long to get through it. I'm looking forward to enjoying more of his brews though. Dogfish Head is even tried making Chicha the old fashioned way, though it didn't exactly work out, since it was more labor intensive than they expected.
Hands down the best health book I read this year was The Definitive H.P. Lovecraft: 67 Tales of Horror in One Volume. Despite being about fictional creatures of terror from unholy abysses, I learned quite a bit from Lovecraft's depiction of the universe. The humans in Lovecraft's stories are baptized into the knowledge that the universe is older and more incomprehensible than they could have ever imagined. While the monstrosities and sublime ancient temples are quite terrifying, what is even more terrifying to the humans in the stories is their realization of how little they can ever really know. Those that get a taste of the mysteries often only do so at a very high price.
They called up some image from deep cells and tissues whose retentive functions are wholly primal and awesomely ancestral
I'm not sure I have any sort of particular cause in terms of diet anymore. It's gotten to the point where I'm just interested in the Paleolithic and not really very concerned with arguing about whether or not a potato is safe to eat or not.
Wouldn't it be nice if our nice little narratives worked out? The ones in which Homo sapiens sapiens is the protagonist and you can trace his illustrious evolution neatly through the ages. And he fits rather nicely in your romantic stories about hunters and mammoths so you can tell people that this is their heritage.
But in reality you don't get your nice story. Instead, you get ages and ages of dust and bones, in which every little shred of a skeleton is a prized, but dim, glimpse into ages long past.
In my anthropology class last year, one of the skull casts that caught my attention was the Kabwe skull, which is estimated to be between 125,000 and 300,000 years old. Not quite Homo Sapiens, the skull has some features of modern humans and some of Neanderthals. Homo rhodesiensis? Homo heidelbergensis? Homo sapiens rhodesiensis? Anthropologists could argue about it all day. Either way, this person died a miserable death. The first known incidence of dental infection in a hominid as far as I know, and the infection was bad enough to put some ugly holes in the bone and eventually kill the individual.
There is only so much you can tell from bones, which leaves lots of room for people to make stuff up. Stable isotope analysis seems quite promising, as they can potentially tell you the source of protein in the diet, but they can only tell that and nothing else, and the isotopes are subject to interpretation. For example, Lierre Keith in her error-ridden Vegetarian Myth claims that stable isotope analysis showed Australopithecus africanus ate meat, but in reality the data only said that the protein was from carbon-13 enriched foods, which could include grasses and sedges as well. Later investigations revealed that the carbon-13 probably was more likely from grasses and sedges, but the data is up for interpretation. Before you tear up your lawn to make dinner, it might be worth remembering that Australopithecus africanus is only thought to be a possible human ancestor and was quite a bit different from a modern human.
That said, stable isotope analysis puts to bed the idea that early Homo sapiens were getting their protein from the Paleolithic equivalent of tofu or the idea that Neanderthals definitely only ate meat (turns out that some ate fish too...maybe).
"Maybe", "later investigations revealed", "thought to be"- these are things that should give you pause whenever you encounter stable isotopes being used to argue about ancient diets. Have I confused you? Good, now you are less vulnerable to the abuse of bones in the name of various causes one way or another.
It can be used to estimate the trophic level and origin of the protein, but it cannot tell you whether the person ate a teeny tiny auroch steak and then 17 potatoes or whether they only ate mammoth. It cannot tell you the percentage of protein in the diet. It cannot tell you how much protein in grams. That information was lost when the person died.
Then there is the use (and mainly misuse) of animal bones and modern data from wild game species to argue various things about ancient diets. I read this latest paper, Man The Fat Hunter, with absolute glee because it uses many of the same questionable methods and comes to an opposite conclusion of many past papers, which overemphasize protein. The questionable method is taking bones of animals possibly consumed by ancient humans and plugging them into an equation with the modern wild game data and then saying this or that about the amount of fat or protein in an ancient diet. In this paper we have elephants featured, which is great, since elephants are very fatty, but unfortunately their presence or absence in bone assemblages is not a food diary. There is no way to know how often elephants were eaten, so there is no way to make an even sort-of accurate conclusion about %elephant and therefore %elephant fat in the diet. Whether or not the hominids in question were able to cook is also a point of contention.
One good thing about the paper is that it does try to address one issue, which is ceilings. In this case, the paper mentions possible ceilings for protein consumption and fiber consumption that could be used to build diet-estimating equations. Unfortunately, there are quite hard to determine, as they are affected by human genetic variation, culture, and environment. For example, there is possible a ceiling on the consumption of raw plant materials based on gut morphology (though if you have only skeletons you can only speculate on this) and toxins, but that ceiling can be raised with access to cooking and processing. To complicate matters further, their food sources may have been things you haven't even thought about eating. You can try to figure it out based on local paleobotany and starch microfossils, which can be hard to read. Once you've established that a microfossil on an ancient tooth is possibly Bromus secalinu, you might be able to figure out a little about how it was processed based on microfossil shape and local conditions and if you have a rich lab you might be able to collect it and do a full nutritional analysis, but you still have no idea how much of the diet it made up.
And what is the protein ceiling? It depends on the rest of the diet, an individual's health, and possibly genetics. Modern genetics adds some depths to the picture. For example, the fact that genetic adaptations for a starch-based diet seem to be part of fairly recent selective sweeps may give us a clue that Paleolithic human ancestors probably weren't eating mainly starch, but statistical genetics is in its infancy.
But genetic variation can add more confusion if we are talking about what to eat now. Many "paleo" dieters have learned the hard way that they carry alleles for hemochromatosis, which means they can over-accumulate iron, which has some pretty nasty effects. It would be interesting to know where this came from, as it clearly would be a liability if an ancient human ate meat-based diet, but ultimately whether or not Paleolithic hominids carried such alleles in high frequency is irrelevant to the millions of men (and some women) who are at risk. This represents a ceiling for them, though it can be modified through modern medical treatment.
Normal is of limited use if you are on the end of the bell curve- this is where personalized medicine and self-experimentation is important
So while it's not completely true we have no idea what Paleolithic hominids ate. We do have some good clues, but reconstructing the diet is pretty hard. That doesn't stop people from trying, but their results are on some pretty shaky ground.
My own method, which is about as accurate as some of these equations, is to observe the fact that a medallion of relatively lean wild boar goes absolutely perfectly with a seared hazelnut crust and dollop of mashed celeriac or potatoes cooked in broth. Maybe there is a reason that dishes containing a protein on a bed of delicious carbs AND fat (but not overpowered by them) is so appealing to so many? Who knows.
Grains are evil. The people in the paleolithic didn't eat them. Amirite? Unfortunately, that hypothesis is contradicted by archeological evidence, but now there is genetic evidence that rice may have been domesticated earlier than thought.
Asian rice, Oryza sativa, is one of world's oldest and most important crop species. Rice is believed to have been domesticated ∼9,000 y ago, although debate on its origin remains contentious. A single-origin model suggests that two main subspecies of Asian rice, indica and japonica, were domesticated from the wild rice O. rufipogon. In contrast, the multiple independent domestication model proposes that these two major rice types were domesticated separately and in different parts of the species range of wild rice. This latter view has gained much support from the observation of strong genetic differentiation between indica and japonica as well as several phylogenetic studies of rice domestication. We reexamine the evolutionary history of domesticated rice by resequencing 630 gene fragments on chromosomes 8, 10, and 12 from a diverse set of wild and domesticated rice accessions. Using patterns of SNPs, we identify 20 putative selective sweeps on these chromosomes in cultivated rice. Demographic modeling based on these SNP data and a diffusion-based approach provide the strongest support for a single domestication origin of rice. Bayesian phylogenetic analyses implementing the multispecies coalescent and using previously published phylogenetic sequence datasets also point to a single origin of Asian domesticated rice. Finally, we date the origin of domestication at ∼8,200–13,500 y ago, depending on the molecular clock estimate that is used, which is consistent with known archaeological data that suggests rice was first cultivated at around this time in the Yangtze Valley of China.
13,500 is older than what many people consider to be the end of the paleolithic, though many consider the paleolithic era to be relative to the region and would characterize a culture eating rice 13,500 years ago to be mesolithic.
The molecular clock also has its share of controversy, as it is based on statistical modeling, but no more than other evidence we have used to build the concept of the paleolithic diet.
I have written about my success with rice and hope to write more about it soon. Maybe I should just start calling my diet the mesolithic diet...
This is one of the better articles I've read lately. It addresses serious errors common to works that cite the Paleolithic and foraging societies at being an apex of human welfare. Some of these errors include
For example Lee wrote that the San "worked" only 20 hours a week. Unfortunately, his definition of work was a little questionable. Turns out they work as much as I do:
investigation revealed that what he defined as subsistence activities occupied adult !Kung for about 2.4 days per week on the average, or for about 20 hours. This rather leisurely work schedule, it is claimed, managed to yield an abundant and nutritionally well-balanced diet. These findings were somewhat puzzling to some anthropologists who have conducted similar investigations in similar societies. Hawkes and O'Connell (1981) observed that the Bushmen figures were one-half to one-fifth of the time required by the Alyawarra, a central Australian foraging group. They expressed some surprise because the !Kung and Alyawarra are very similar in habitat as well as technology. The difference, it turned out, was explainable by Hawkes and O'Connell's definition of work: in their calculations of work, they included time spent in processing food as well as hunting and gathering it...."In addition there are the important tasks of manufacturing and maintaining their tool kit and, of course, housework-for the !Kung this involves food preparation, butchery, drawing water and gathering firewood, washing utensils, and cleaning the living space. These tasks take many hours a week" (Lee 1984:51-52).6 When these tasks are added to "subsistence work," the estimate per week is 44.5 hours for men and 40.1 hours for women. Lee is quick to add that these figures are well below the 40 or so hours per week that people in our own society spend above their wage-paid job doing housework, shopping, and other household chores. What seems to be at issue here is what we mean by terms such as "work" and "leisure" in the context of hunting-gathering societies---or, indeed, in the context of any society.
What about all that time spent lounging about?
And then there are the G/wi Bushmen, who reside in the central Kalahari. According to Silberbauer (1981:274- 78), they spend a good part of the day (from about 10 A.M. to about 4 P.M.) resting in the shade, not because they have "chosen" leisure over work or have limited wants, but because to venture out in the blistering sun for any time would expose them to dehydration and heatstroke. Throughout much of the year, there is little cloud cover to provide some relief from the withering heat; unshaded temperatures can reach 60'C (140'F), and sand temperatures as high as 720C (161 F) have been recorded. During the early summer months, all the G/wi lose weight and complain of persistent hunger and thirst (Silberbauer 1981:274). Hardly a "picnic outing on the Thames."
Also sheds further doubt on how well humans are actually adapated to the savanna.
What about using the !Kung diet to make inferences about what a healthy Paleolithic diet was?
Truswell and Hansen (1976:189-90) cite a string of biomedical researchers who have raised doubts about the nutritional adequacy of the !Kung diet, one going so far as to characterize one Bushmen group as being a "clear case of semi- starvation." Truswell and Hansen (1976:190-91) themselves have concluded that the data suggest "chronic or seasonal calorie insufficiency may be a major reason why San do not reach the same adult stature as most other people."... although he softened his opposition somewhat by conceding that the smallness of the !Kung might have something to do with undernutrition during childhood and adolescence, and he went on to note that !Kung raised on cattle posts on a Bantu diet of milk and grain grow significantly taller (Lee 1979:291).
This paper also mentions the fact that the vast majority of the !Kung consider mongongo nuts an undesirable fallback food. People who want to exploit the !Kung to talk about the Paleolithic tend to believe that they have been foraging since the Paleolithic and the nearly agropastoral people have had little effect on their lifestyle. I will address more of this myth in later posts, but needless to say, the evidence points to the fact that the !Kung have had trading relationships with agropastoralists and their current state is much more precarious nutritionally than it was in the past.
What is mainly missing from their foraging diet these days is fat:
We hear so much these days about the overconsumption of fat in the modern industrial diet that we sometimes forget how important some level of fat consumption is to normal human growth and the maintenance of healthy bodily functions. Animal fat, says Reader (1998:124) is "the proper measure of affluence.".... Hayden's (1981:421) observation is especially relevant here: "I was astounded the first time I saw Western Desert Aborigines ... kill a kangaroo, examine the intestines for fat, and abandon the carcass where it lay because it was too lean. Upon making a kill, Aborigine hunters always open the intestinal cavity and check the fat content. Virtually every ethnographer with whom I have discussed this observation confirms it, yet such details are seldom reported in the literature."
But at least they all love to share with each other...right?
Here, we were told, in the more marginal areas of the world were societies that were depicted as just the opposite of the industrial West, societies characterized by egalitarianism, widespread sharing of resources, an indifference to material possessions, societies whose members seemed to live in harmony with nature and one another and whose wants were modest and easily satisfied....sharing that goes on seems to be as much motivated by jealousy and envy as it is by any value of generosity or a "liberal custom of sharing." In his survey of foraging societies, Kelly (1995:164-65) notes that "Sharing... strains relations between people. Consequently, many foragers try to find ways to avoid its demands .... Students new to anthropology..,. are often disappointed to learn that these acts of sharing come no more naturally to hunter- gatherers than to members of industrial societies."...(1982:55) recounts the incident of an elder Bushman who asked him for a blanket. When Lee responded that he would just give it away, the elderly Bushman replied, "All my life I've been giving, giving; today I am old and want something for myself." Lee adds that the sentiments expressed by this elder were not unique. Perhaps "human nature" is not as different from society to society as we have been led to believe.
Perhaps there was a golden age, where fatty game was more abundant and sharing came easily. But the Bushman don't tell us much about that and overall it remainds a speculation.
In negative reviews of books on so-called "attachment parenting" like The Continuum Concept people often harp on about how it's "smothering" and emphasis the children at the expense of other social relationships. I suspect those people haven't read the book. The foraging horticulturalists in that book, for example, do breastfeed their children, sleep with them, and carry them around close to their bodies. But overall, these women are not "smothering." The book describes an incident where a toddler is carrying around a rather sharp knife and banging it around. The mother ignores him and chats with another mother. That is, until the toddler drops the knife. Then the mother picks the knife up and gives it back to the kid. Their culture is one where children are biologically fulfilled, but socially the children are not the center of the social life.
Contrast that with our culture, where children are biologically unfulfilled, but our social culture is obsessed with them. We have to endow them with "good self esteem" and make sure they don't get hurt on "dangerous" playgrounds. Our time with our children has increased, but not through passive activities like having dinner with them, but through taking them to extracurricular activities and helping them with homework.
There is an interesting article in The Atlantic asking whether this has been a good thing. The author is a therapist quite surprised to see so many patients who had attentive "good" parents:
Until, one day, another question occurred to me: Was it possible these parents had done too much?
Here I was, seeing the flesh-and-blood results of the kind of parenting that my peers and I were trying to practice with our own kids, precisely so that they wouldn’t end up on a therapist’s couch one day. We were running ourselves ragged in a herculean effort to do right by our kids—yet what seemed like grown-up versions of them were sitting in our offices, saying they felt empty, confused, and anxious. Back in graduate school, the clinical focus had always been on how the lack of parental attunement affects the child. It never occurred to any of us to ask, what if the parents are too attuned? What happens to those kids?
I became seriously worried about raising my own children when I was a camp counselor in a wealthy suburban area and found out the games that were "banned", which included:
- Star Wars (and anything else with wars)
- Cowboys and Indians (and anything else politically incorrect)
- Police and Robbers (and anything else with "weapons" even if you used your hand and went "bang bang".)
- Good old fashioned Tag and Hide and Go Seek... too "dangerous"
Meanwhile, everyone was unconcerned with the massive amounts of sugar we fed those kids. I was also quite alarmed by the large "food allergy" table we maintained and heavily policed. I don't remember having such things when I was a kid. Seemed like every child was allergic to something.
When I was a kid we ate junk food, but we played Star Wars and often our version of Dagobah was a seriously gross insect and snake infested creek...completely unsupervised. I'm sure it was probiotic and tons of exercise :) I'm hoping my kids can have a childhood like that, but seems like it's bucking the trend enough that it means public school and whatnot just aren't options, despite some backlash such as Free Range Kids. I'd love to find a private school that has a good philosophy, but since I was homeschooled myself, I know it doesn't kill you or anything :P Increasingly, members of the ancestral health community seem interested in this approach, given that most public and private schools
- feed kids sugar and fried crap, among other poisonous foods
- force them to sit for hours and hours a day when they should be playing outside
- structure them into a social strata alien to our evolutionary context. I wouldn't be surprised if putting children of all the same age together all day instead of mixing children by ages and with elders is the cause of much social stresses like bullying.
- socialize them into a homogenous worldview, causing the loss of unique cultures
Suggestions that humans may have obtained more calories from SCFA in the past are rooted in estimates of fiber consumption from the Paleolithic. Evidence is rather sparse and limited to coprolites. In the burgeoning field of evolutionary medicine, anthropologists have become very interested in the Paleolithic diet and its relevance for promoting health today. Some of the landmark papers in the field have cited these coprolite studies as evidence for fiber intakes as high as 150 grams as day, well over what any known human culture currently consumes (M. Konner & S Boyd Eaton, 2010). Even if the method for estimating fiber consumption from coprolites is accurate, they may not support the conclusion that they represent some species level optimal and may in fact suggest a ceiling for safe fiber consumption that great apes do not share.
The argument for studying the Paleolithic diet in order to see what is optimal for modern humans to eat stems from the fact that archeological remains suggest that Paleolithic hunter-gatherers were healthier than their agrarian descendents (S B Eaton, M. J. Konner, & Shostak, 1996). Generally, they were taller, had fewer skeletal pathologies, and their teeth were in much better condition 1. One of the sources for these high fiber estimates is coprolites from prehistoric Indians in the North American desert southwest, who consumed as much as 150 to 225 grams of fiber a day (Leach & Sobolik, 2010). Far from being in admirable health, evidence shows they had extensive dental caries. Some have speculated that this was caused by high levels of phytoliths in their diet, which wore down their teeth (Danielson & Reinhard, 1998). But other populations with extensive tooth wear do not exhibit high levels of caries2 (B. H. Smith, 1984). This raises the question of whether or not wear really caused their caries or if perhaps their fiber consumption caused them.
Clues come from modern nutritional biochemistry. Dietary fiber has the ability to reduce blood levels of Vitamin D, which is vital in tooth and bone mineralization (Batchelor & Compston, 1983). This may be the reason that some populations with high-fiber diets in Asia exhibit vitamin D deficiency despite adequate sun exposure. Children on macrobiotic diets, which are high in fiber, have higher than normal rates of rickets (Dagnelie et al., 1990). However, macrobiotic diets and those of rural Asians are notably low in animal products and high in plants different from those our Paleolithic ancestors ate, which contain mineral-leaching phytic acid (Raboy, 2001). The fiber in other primate diets and presumably in Paleolithic diets is mostly dicot vegetable fiber, whereas modern grain fibers come from monocotyledonous plants (Milton, 1989). It’s also possible that these problems would not occur at Paleolithic levels of animal product consumption, as animal products are rich sources of vitamin D and minerals (M. Konner & S Boyd Eaton, 2010).
Other anthropologists have tried to infer ancestral fiber consumption based on the diets of modern foraging populations and agrarians, but these have run into their own problems. Incorrect laboratory methods of analysis marred early data sets, though some of these data sets are still being cited in newer papers. Some examples include an estimate for Ugandan fiber consumption of 150 grams a day that was revised to 70 grams a day and an estimate for Kenyans of 130 grams a day reduced to 86 grams a day (Wrangham, Conklin-Brittain, & C. C. Smith, 2002). Other problems have come from analyzing fiber outside of dietary context. For example, much like we don’t consume the peels of bananas, Hadza don’t consume whole wild tubers. When they eat tubers, they chew them and the excess fiber is spit out. Obviously estimates of fiber consumption based on the whole tuber are overestimates (Schoeninger, 2001).
Fiber spit out by the Hadza
Given this, the use of extremely high estimates for Paleolithic fiber intake based on limited data as a baseline for optimal consumption seems misplaced. No known culture consumes over 100 grams of fiber. The highest recent estimate was 86 grams for some agrarian cultures in Africa (Wrangham et al., 2002).
Some of the issue is also overemphasis on fiber, when other food constituents that play a similar role may have been more important in human evolution. Early optimism that high fiber could prevent many diseases of civilization like heart disease and type II diabetes spurred many studies on the matter. These have had mixed results. There have been several expensive failed studies such as the forty-nine thousand women Dietary Modification Trial of the Women’s Health Initiative which found that increasing dietary fiber had no effect on risk of colon cancer, breast cancer, or heart disease and no effect on weight loss (Beresford et al., 2006). Those who cling to the fiber hypothesis insist that the trials have not been long enough or high enough in fiber (Byers, 2000).
Focus on fiber in the past was on its abilities as indigestible bulking matter to increase digestive transit time and bind up certain food constituents. (J. Smith, Yokoyama, & German, 1998). The dominant theory was that slower transit time allowed carcinogens and other potential toxins to fester in the body. This idea that spawned a cottage industry of quacks and religious movements advertising “cleanses” (Kellogg, 1923) that has remained robust to this day , but has not stood up to scientific scrutiny.
Next up: fiber or bacteria??
1. This argument seems suspect, since while early agrarians seemed to have had high levels of disease based on skeletal evidence, later agrarians and pastoralists are often much taller than people in the Paleolithic and also exhibit low incidence of pathology.
2. Including cultures that purposefully file down their teeth
Batchelor, A. J., & Compston, J. E. (1983). Reduced plasma half-life of radio-labelled 25-hydroxyvitamin D3 in subjects receiving a high-fibre diet. The British journal of nutrition, 49(2), 213-6. Retrieved May 2, 2011, from http://www.ncbi.nlm.nih.gov/pubmed/6299329.
Beresford, S. a a, Johnson, K. C., Ritenbaugh, C., Lasser, N. L., Snetselaar, L. G., Black, H. R., et al. (2006). Low-fat dietary pattern and risk of colorectal cancer: the Womenʼs Health Initiative Randomized Controlled Dietary Modification Trial. JAMA : the journal of the American Medical Association, 295(6), 643-54. doi: 10.1001/jama.295.6.643.
Byers, T. (2000). Diet, colorectal adenomas, and colorectal cancer. The New England journal of medicine, 342(16), 1206-7. doi: 10.1056/NEJM200004203421609.
Dagnelie, P., Vergote, F., Staveren, W. van, Berg, H. van den, Dingjan, P., & Hautvast, J. (1990). High prevalence of rickets in infants on macrobiotic diets. Am J Clin Nutr, 51(2), 202-208. Retrieved May 2, 2011, from http://www.ajcn.org/cgi/content/abstract/51/2/202.
Danielson, D. R., & Reinhard, K. J. (1998). Human dental microwear caused by calcium oxalate phytoliths in prehistoric diet of the lower Pecos region, Texas. American journal of physical anthropology, 107(3), 297-304. doi: 10.1002/(SICI)1096-8644(199811)107:3<297::AID-AJPA6>3.0.CO;2-M.
Eaton, S B, Konner, M. J., & Shostak, M. (1996). An evolutionary perspective enhances understanding of human nutritional requirements. The Journal of nutrition, 126(6), 1732-40. Retrieved March 26, 2011, from http://www.ncbi.nlm.nih.gov/pubmed/8648449.
Kellogg, D. J. H. (1923). Natural Diet of Man.
Konner, M., & Eaton, S Boyd. (2010). Paleolithic nutrition: twenty-five years later. Nutrition in clinical practice : official publication of the American Society for Parenteral and Enteral Nutrition, 25(6), 594-602. doi: 10.1177/0884533610385702.
Leach, J. D., & Sobolik, K. D. (2010). High dietary intake of prebiotic inulin-type fructans in the prehistoric Chihuahuan Desert. British Journal of Nutrition, 103(11), 1558-1561. Retrieved May 10, 2011, from http://journals.cambridge.org/abstract_S0007114510000966.
Milton, K. (1989). Primate diets and gut morphology: implications for hominid evolution. In M. Harris & E. B. Ross (Eds.), Food and Evolution: Toward a Theory of Human Food Habits (p. 93). Temple University Press. Retrieved May 8, 2011, from http://books.google.com/books?hl=en&lr=&id=xHYxSHr86T8C&pgis=1.
Raboy, V. (2001). Seeds for a better future: “low phytate” grains help to overcome malnutrition and reduce pollution. Trends in plant science, 6(10), 458-62. Retrieved May 9, 2011, from http://www.ncbi.nlm.nih.gov/pubmed/11590064.
Schoeninger, M. (2001). Composition of Tubers Used by Hadza Foragers of Tanzania. Journal of Food Composition and Analysis, 14(1), 15-25. doi: 10.1006/jfca.2000.0961.
Smith, B. H. (1984). Patterns of molar wear in hunger-gatherers and agriculturalists. American journal of physical anthropology, 63(1), 39-56. doi: 10.1002/ajpa.1330630107.
Smith, J., Yokoyama, W., & German, J. B. (1998). Butyric Acid from the Diet: Actions at the Level of Gene Expression. Critical Reviews in Food Science and Nutrition, 38(4), 259-297. doi: 10.1080/10408699891274200.
Wrangham, R., Conklin-Brittain, N.-L., & Smith, C. C. (2002). A Two-Stage Model of Increased Dietary Quality in Early Hominid Evolution: The Role of Fiber. In P. S. Ungar & M. F. Teaford (Eds.), Human diet: its origin and evolution (p. 206). Greenwood Publishing Group. Retrieved May 9, 2011, from http://books.google.com/books?hl=en&lr=&id=6GDELypdTUcC&pgis=1.
True or false:
Unfortunately, a lot of people out there would answer "true" to these questions. This makes me sad. Every plant food and many animal foods contain potentially toxic substances, but as Paracelsus said "the dose makes the poison." Besides that, there is ample evidence that paleolithic people ate potentially toxic foods like cycads, seeds, and roots. The advent of cooking is debated pretty heavily in anthropology, but everyone agrees it was invented in the paleolithic, though exactly when is heavily disputed. As my professors always said "it's hard to determine much with a sample size in the single digits." Unfortunately, in physical anthropology that's often the amount of samples available.
Beyond that, I strongly recommend listening to the Paleo Solution episode with Matt Lalonde on why this whole "what did paleolithic people eat exactly" discussion is stupid. And Dr. Kurt Harris' post on Orthorexia.
One of my favorite jokes with Chris Masterjohn is "I can't kiss you because you contain lectins" ;) Of course, after saying that, I do kiss him and I could not care less about the lectins he contains, which I also contain.
Avoiding specific lectins might be worth it for those of us battling illness, but only profound ignorance would condemn a food (or a man) because lectins are present. How about trying to figure what's wrong and eliminating foods as needed instead of looking for problems where there are none?