This blog is about the intersection between evolutionary biology and food. But also about practical applications, sustainable agriculture, and general tasty things.
Melissa McEwen
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05/22/2013 - 17:59
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.
05/13/2013 - 20:48
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.
04/08/2013 - 20:07
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.
02/19/2013 - 17:09
When people use the contact form on the bottom of this site, maybe they should take a few seconds and think about two things I don't tolerate very well, which are
- packaged industrial products being sold under "real food" or "paleo" labels
- complete and utter misuse of history to sell a particular diet
Maybe don't send me that stuff, because I will post about it, and I will criticize it. Or maybe on the latter case, just leave the historical narrative out of your spiel if you can't waste more than an hour thinking about what it might actually imply.
One thing I really regret is when I first got healthy by eating a paleo diet, I thought that if everyone just ate like me, they could have a slim body like mine. It didn't seem that hard to me. So I became a zealot about it. But that process of being a zealot forced me to talk with a wide range of people about their experiences with food and health- from relatives to people I met at paleo meetups in real life. What shocked me were the people who ate like me, some of them ate "better" than me, and yet they were struggling with their weight. I even met people who gained weight on diets like mine. It was eye-opening.
And then there was the process of me discontinuing my strict diet, once when I moved to Europe, and next after I was having low blood pressure issues. I was talking to a friend who lost a lot of weight on paleo successfully and now works...making pizza. We were both joking how we have worried that we were going to suddenly gain a bunch of weight. But it never happens. It's not like we returned to a junk food diet, but I'm not going to turn down some ice cream or homemade pizza. And yet there are people right now turning down the kinds of things who can't seem to slim down. And then there are are fair number of people who slim down on diets full of paleo demonized foods like legumes and whole grains.
Some of them realize that health is about more than being slim, and while gaining weight might be a bad sign, the fact that they can lose a little and feel healthier is more than satisfying. Others however give up, disenchanted with the promises of a slim figure, dismissing it as just another fad diet.
Recently Jonathan Bailor sent me a contact email not once, but twice with his new "Slim is Simple" video to celebrate the creation of a non-profit devoted to distributing his educational material on healthy eating. I was surprised that so many got excited by this video. I criticized it on Twitter and some people were upset by that, saying it was a great educational tool and we need more such "simple" tools. No reason to be obsessed with scientific accuracy. Now I don't think I have that problem- I have recommended books that are quite imperfect on this blog many times from The Primal Blueprint to The Paleo Solution, but I don't recommend something unless I feel it has a useful and correct core.
Luckily I wasn't the only one who saw right through this video, Beth at Weight Maven, also posted a skeptical take on it. Evelyn has also written about Jonathan's other work before. I won't even get into his questionable calorie math that doesn't seem to bother with the fat that the correct equation takes maintence, which depends on body size, into account.
But I also would love to see more books that simplify eating without bordering on inaccurate propaganda like this video. I felt like I was watching a cult indoctrination film. Not only that, but it would seem its bolsters didn't even notice he's recommending a diet that is pretty different from the one they recommend- a diet based on three pillars of protein, fiber, and water. Eat as much as you want of those three things (maybe it helps that if you eat too much of the first two, you'll get diarrhea).
That's right- have as much protein as you want on this diet, have twice as much as normal, you'll be so satiated you'll supposedly forget about ice cream.I think this is exactly the kind of diet I coined the term "faileo" to describe (though sadly I feel this eventually contributed to a culture that somehow thinks you can guzzle as much coconut oil and bacon fat as you want, when I was kind of just trying to get people on board with more reasonable things like lamb shanks). The language is also exactly what many of us have tried to get away from, like the idea that we are "designed" for certain "clean" (an excessively moralistic word reminiscent of Kellogg and other health puritans) foods. Other foods, like starches and sugars (including most fruit- only citrus and berries are given a pass), will "clog our body."
But then I gets weird, because he says "almost everyone stayed healthy and fit without even trying until very recently" and the visuals for this are very interesting:
So we have an early bipedal ancestor, and than an Egyptian, and Pioneer, and someone who looks like they are from the 40s or 50s. Oh and a rather curvy person, who we presumably don't want to be...if only we knew what those Egyptians did. But Egyptians ate diet rich in bread and beer. Wait, I thought all these foods were the ones the video describes as "unnatural" and are responsible for our modern "clogs"? Hmm, well maybe we'll see about the pioneer woman. American pioneers had access to much more meat and fat than the average Ancient Egyptian, but they also ate things like biscuits and hoe cakes. 40s to the 60s? Well I collect cookbooks from those eras and they are certainly not full of an austere cuisine of protein, fiber, and water. Even if he had used the typical types of people that paleo dieters hold up as examples- the Hadza, The !Kung, the Kitavans, and other modern peoples who still live foraging lifestyles and remain very healthy, it would not make sense, because their diets contain a large amount of starch and even simple sugars.
Another use of history offender is Dr. Lustig in his new book Fat Chance: Beating the Odds Against Sugar, Processed Food, Obesity, and Disease. Others are more qualified to comment on the biochemistry errors in this book, but the food history in this book is so inaccurate that I wonder if publishers even bother to employ fact-checkers any more. His take on food history involves dividing ancient people into "hunters" mythic fat-burning intermittent fasting meat-guzzlers who "didn't know what a carbohydrate was and they didn't need to." The modern remnants are the Maasai and Inuit. Then there were the "gatherers" who ate carbohydrates and protein in the form of fruits and vegetables, "this is the basis for today's vegan diet. It is practiced in multiple cultures around the globe, because if you grow your own food, that's what's available." Yes...the vegan tribes of India, oh wait, there is no such thing. And has Lustig ever raised his own food or visited a farm? Where do you think most farmers are getting fertilizer from? Hint: it's not vegan.
And the Maasai, while they may sometimes be fat burners, are not a low-carb culture. As for ancient foragers, there is a reason they have been called hunter-gatherers, not hunters AND gatherers. In fact the vast majority of foraging peoples in the Ethnographic Atlas eat fairly mixed diets, the people who are primarily hunters or gatherers are exceptions.
But Lustig has to make up this false narrative so he can get to his all-encompassing theory of all our problems (and also because for some weird reason he wants to pander to both the Atkins and plant-based folks, a weird thread in this book), which is the "Omnivore's Curse"- "it wasn't until we became gourmets, eating fat and carbohydrate in the same meal, that our cells first felt the wrath of mitochondrial wear and tear." Apparently, with the advent of farming we started mixing fat and carbohydrates together in meals and thus we became diseased, because in nature there are no foods that have both things, which means somehow that we should take our lessons and cease our evil cooking of potatoes in butter. "This accounts for the appearance of metabolic disease with the advent of trade in the early seventeenth century; before that, food was still a function of what you killed or you grew yourself. Eventually, we became gourmands, eating fat and carbohydrate in the same food."
Reminds me of my maxim not to take advice on food from people who don't actually seem to like it very much. My friends and I have a historical eating club and this Saturday is our dinner based on ancient Mesopotamia. I still have some mead (liquid carbohydrates mmm) left over from our Viking dinner, though we might have some ancient beer as well. For dinner I am making lard-rubbed goat leg with cumin, mastic, coriander, mint, and ginger. There will be sides of roasted barley and roots. Yes, I will be mixing carbohydrates, fat, and protein in one meal, which presumably people have been doing since they have been cooking. Pottery dates well into the Paleolithic, and before that people probably used other containers to mix things together. We know they were cooking because they left residues of grease and boiled fruits and all sorts of other things. Because humans are curious creatures and some of us really do like to play with our food (though as Gary Nabhan has pointed out, there may be some evolutionary reasons some cultures adopted things like spices).
Some people cook less than others- for example the Hadza don't seem to cook very many "recipes" though they do mix baobab (which contains both fat and carbohydrate) with honey for a drink sometimes. It's funny that Lustig later mentions that Ancel Keys in his heart disease study left out populations like those in Tokelau- in Tokelau their diet is starch and coconut. If mixing fat and carbohydrate were an issue, we would have been the way we are now for a very long time. Not that I think ancient people were perfectly healthy- for example, both Egyptian and Inuit mummies show atherosclerosis, though back then it may have been caused by constant infections and cooking smoke inhalation rather than food and there is no evidence it caused any mummy's death. Lustig does also make a good point that heart disease was a problem in the 1930s, back before the "obesity epidemic".
When I think of my very slim (though probably wearing a corset) great-great grandmother pictured here, I don't think of diets based on protein, fiber, and water. I think of people who ate reasonable natural homemade food. The same food I eat now. I doubt she would have touched things like the Slim is Simple Peanut Butter Pie (which contains ingredients I actually do try to avoid: low-fat dairy, industrial whey protein isolate, and extremely high omega-6 peanut butter, cooked almond flour...he recommends leaving the honey out of the crust, which is funny because it's probably one of the healthier ingredients) with a ten foot pole.
She didn't count calories, and neither have I. As someone who eats made-from-scratch foods that are highly variable it would be pretty pointless for me to count calories, as it would be inaccurate. I know when I'm losing weight I have a calorie deficit though, even if it is going to not be possible to quantify it accurately. Some people find success with trying to do the math, but I always found it easier to try things that have been shown in studies to subconsciously reduce the amount of calories eaten. One of these is to eat a lot of protein, which is funny because that's one of Bailor's main strategies. Though it certainly never made me stop thinking of other foods, and I had significant energy issues when I was on the very high-protein, low fat, high fiber kind of diet Bailor advocates. Frankly, I felt sick and catatonic, but I guess his diet works for some people, and not for others, the same way some weight loss diets work for some and not for others. Because nothing to do with the human body is simple. Slim is not simple.
08/19/2012 - 02:02
Possible too gross for some, via John Hawks, this article that mentions a most interesting experiment mentioned in an article on strange science:
yum?
If you like shrews, especially if you like them parboiled, you'll want to devour a 1994 study published in the Journal of Archaeological Science. Called Human Digestive Effects on a Micromammalian Skeleton, it explains how and why one of its authors – either Brian D Crandall or Peter W Stahl; we are not told which – ate and excreted a 90mm-long (excluding the tail, which added another 24mm) northern short-tailed shrew (Blarina brevicauda).
This was, in technical terms, "a preliminary study of human digestive effects on a small insectivore skeleton", with "a brief discussion of the results and their archaeological implications". Crandall and Stahl were anthropologists at the State University of New York in Binghamton. The shrew was a local specimen, procured via trapping at an unspecified location not far from the school. For the experiment's input, preparation was exacting. After being skinned and eviscerated, the report says, "the carcass was lightly boiled for approximately 2 minutes and swallowed without mastication in hind and fore limb, head, and body and tail portions".
Here's how Crandall and Stahl handled the output: "Faecal matter was collected for the following 3 days. Each faeces was stirred in a pan of warm water until completely disintegrated. This solution was then decanted through a quadruple-layered cheesecloth mesh. Sieved contents were rinsed with a dilute detergent solution and examined with a hand lens for bone remains." They then examined the most interesting bits with a scanning electron microscope, at magnifications ranging from 10 to 1,000 times.
A shrew has lots of bony parts. All of them entered Crandall's gullet, or maybe Stahl's. But despite extraordinary efforts to find and account for each bone at journey's end, many went missing. One of the major jawbones disappeared. So did four of the 12 molar teeth, several of the major leg and foot bones, nearly all of the toe bones, and all but one of the 31 vertebrae. And the skull, reputedly a very hard chunk of bone, emerged with what the report calls "significant damage".
The vanishing startled the scientists. Remember, they emphasise in their paper, that this meal was simply gulped down: "The shrew was ingested without chewing; any damage occurred as the remains were processed internally. Mastication undoubtedly damages bone, but the effects of this process are perhaps repeated in the acidic, churning environment of the stomach."
Chewing, they almost scream at their colleagues, is only part of the story. In each little heap of remains from ancient meals, there be mystery aplenty. Prior to this experiment, archaeologists had to, and did, make all kinds of assumptions about the animal bones they dug up, especially what those partial skeletons might indicate about the people who presumably consumed them. Crandall and Stahl, through their disciplined lack of mastication, have given their colleagues something toothsome to think about.
The human stomach was more capable at digesting bones than they expected. This isn't terribly surprising to me, as many cultures consume whole bone-in animals and there is plenty of archaeological evidence for this. Here's a bit from John Speth's book:
Well-preserved prehistoric human coprolites (feces) recovered in large numbers from dry caves throughout western North America are full of pulverized bone fragments, including pieces of broken skulls, as well as fur and feathers, indicating that rodents, rabbits, birds, lizards, snakes, and amphibians were often cooked whole, pounded in a wooden mortar or on a milling stone, and then consumed in their entirety – bones, fur, feathers, and all, including the precious DHA in the brains (Reinhard et al. 2007; Sobolik 1993; Yohe et al. 1991).
Evidence from some of these coprolites (fossilized poo) shows the entire animal was probably consumed with no butchery and some animals were consumed completely raw(PDF)
It would appear that the Desha people at Dust Devil Cave ate rabbit legs more-or-less whole, then pounded the rest of the carcass before eating it... The consumption of wood rats (Neotoma spp.), also known as pack rats, has been noted ethnographically. They were regarded as good food by the Yaqui (Spicer, 1954: 49), constituted a staple for all tribes along the lower Colorado River (Castetter & Bell, 1951: 217), and many were eaten by the Tohono O’Odham. The Cocopah set fire to their nests, clubbing the rats as they emerged, undoubtedly fragmenting some bone in the process.
In the past, there was perhaps more focus on big game hunting. And while big game bones are nice, they are harder to process than little animal bones. Primates have probably been digesting little bones for much longer than they have been breaking open larger bones for marrow. Excessive focus on big game has led to ignoring the contribution of small game to human nutrition, which has also led to the misconception that women don't hunt since some anthropologists classified small game hunting as gathering.
It would be interesting to know if other primates can also digest bone. Chimpanzees seem to degrade the bones of other primates they hunt and consume (PDF). Salad lovers might be interested to know that when chimpanzees consume a meal of meat, they consume it with leaves.
It would also be fascinating to know if humans process the same ability as some other carnivores to use animal parts as de-facto fiber and ferment it into SCFA.
At some point in human evolution, humans developed technology to extract nutrients from bones more efficient than their own stomaches, which is referred to as "grease processing" in many archaeological papers, but is close to what we do in making broths today. It is understandable why humans developed this, considering a meaty meal for a chimpanzee can take nearly the entire day to consume. Frankly, while I like a 6-hour tasting menu sometimes, I don't have time for that very often.
But today, could many humans handle bone? With dietary and medical factors like widespread use of proton pump inhibitors reducing acidity of the digestive tract, are we losing this capability?
For the record, I have never eaten a whole rodent bones and all, though I have eaten many small whole bony fish. There is some indication that humans degrade fish bones more completely, leading to their relative scarcity in coprolites and underestimation of their importance in diet.
Perhaps whole rat eating is becoming trendy again though, a posh rat dinner was featured in the New York Times recently.
10/27/2011 - 11:20
I'm going to call the paleo diet portrayed in the media the PaleoStrawman diet. It contains only lean meat and non-starchy vegetables. The meat comes from factory farms. The latest place it has showed up on is NPR, where anthropologist Barbara King contends that it is not the way to a healthy future for the world. She says she has interacted with paleo dieters online and has read Paleo magazine, but it doesn't show at all.
She says:
- Paleo means more factory farmed animals
- Paleo means more grains diverted from feeding the hungry to feeding livestock
- Paleo has a dearth of carbohydrates
- Paleo is a monolith
- Paleo is bad for a crowded planet
I think there are only a few holdouts in the lean meat camp. The no-starch camp is in its death throes as we speak, embracing a doctor who believes anyone who eats carbohydrates has diabetes and drfiting further into denialism territory. There is not a single paleo book on the market that I can think of that advocates eating grain-fed meat. PaleoStrawman has gotten considerable criticism from within the ancestral health community.
But in the end, it doesn't matter, because even if the paleo diet involved chomping down on grain-fed steaks all day, it would have nothing to do with our ability to feed the world.
We all want to believe our diet has the power to change the world, but it does not. If every person in NYC chose to stop eating grain-fed meat today, it would not help people in Africa. When grain doesn't go to the feedlot, it doesn't get sent to Africa either. Farmers would chose to grow less grain or grow it for biofuels. We already produce enough food to feed the entire population of the world. What is hurting poor countries is political corruption and poor infrastructure. What poor countries need is good leaders and investment in infrastructure and education.
As for vegetarianism and factory farming, sadly, the worst offenders in factory farming are vegetarian products such as dairy and eggs. Vegetarianism is more efficient compared to grain-fed meat partially because the industrialization of eggs and dairy has made these industries very productive. However, they are the most cruel and environmentally destructive animal industries besides the industrial hog farm industry. Jonathan Safran Foer, certainly no paleo dieter, recommends in Eating Animals that if you care about animals, conventional eggs and dairy are the first foods you eliminate.
As for the anthropology, it makes little sense to worry about australopithecines being vegetarian, a hominid with significantly different morphology. Or to worry about the local context very much. Of course people ate diverse diets then. You can eat a diverse locally-based paleo diet now. And for those of us in the North, it makes absolute sense to eat meat rather than trucked-in grain products. Solutions for world hunger do not have to involve the same diet for everyone. Sustainable solutions will be local solutions.
10/07/2011 - 13:55
In a world where college classes, particularly large impersonal introductory ones, are often more pricey than they are worth, it's wise to learn how to study on your own. My inbox is a huge mess, but I have gotten towards the bottom and found an email where Richard from Free the Animal asked about anthropology texts. Here are my favorites, most of them recommended to me by Professor Ralph Holloway:
The Human Career by Richard G. Klein is a pretty great all-around textbook with lots of theories, information, and pictures.
It does assume a basic knowledge of human evolution though, so if you are a beginner the Introduction to Physical Anthropology, How Humans Evolved, Primate Adaptation and Evolution, or The Emergence of Humans.
If you want to improve your ability to read about bones, I suggest An Introduction to Human Evolutionary Anatomy or The Human Bone Manual.
Of course these college textbooks are quite expensive, but if you read one and you read it well you are probably learning as much, if not more, than you would be taking an anthropology course. I think it is worth it to get the most recent editions because this field is so active right now and there have been a lot of very interesting recent revelations.
If you have any personal recommendations, let me know in the comments!
09/06/2011 - 18:52
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:
"Clues from the colon: How this organ illuminates our digestive evolution and microniche" by Melissa McEwen from Ancestry on Vimeo.
View more presentations from Ancestry
[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.
[applause]
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.
[applause]
08/26/2011 - 09:27
I've tangled with a lot of opinionated folks since I started this blog. But I never expected the response I got to my post on Lierre Keith. It reminds me that as much as vegans and animal rights activists irk me, we are all trying to make civilization a better place, even if our ultimate visions are different. Wasn't there a movie about this?
Anti-civilization ideologues see the injustices of the world and can only envision tearing everything down, which is sadly based on a vision of pre-civilization humans that is doubtful and the idea that the earth is dying, which is also doubtful. If we are to tear down civilization, I'd think we'd want our tenets to be based on ideas that are true beyond a reasonable doubt. Besides that, the overwhelming evidence is that places that descend into anarchy see resource degradation accelerate. For accounts of this, see Jared Diamond's Collapse.
Overwhelmingly, my regular readers were supportive, but apparently my post was posted on an anti-civilization forum and they sicced their cult on me (not an isolated event, certainly, as can be seen on any blog post critical of Jensen & co.) there were several very disturbing comments and I had to turn on moderation. At some point I became so busy that the moderation queue got out of hand and so I closed comments. At that point I started receiving some disturbing emails. My mother said I should pull the post, arguing that even though it may be true it wasn't worth antagonizing people who embrace violence. I felt a little like The Voracious Vegan. Like her, I absolutely refuse to delete my post, despite being threatened and called a corporate shill (and worse). Don't feel sorry for me: I welcome this. It only confirms my desire to see the paleo/ancestral health community educated about Lierre's agenda. That said, this is a blog about paleo/ancestral health and from now on I will delete comments unless they are constructive. Their forum is kept under lock and key (possibly because they are advocating violence and terrorism) and Jensen's "reading club" brokers no criticism, I have no obligation to keep mine open. Yes, I kind of let the comments on the last post go to hell. Having moderated many online communities, I am aware that no one benefits from anarchy within a small community. And there is no use arguing with people who have their minds made up that civilization must be destroyed at any cost.
So my new comment policy is that I will not publish your comment at all if there is any evidence you are here just to troll. If you are a regular commenter here I will put you on a whitelist so your comments don't have to be moderated.
I suppose this is what happens when your evidence for your absolute convinction that civilization is evil and much be destroyed consists of a pitiably small sample set of bones, tiny groups of surviving foraging people who have been influenced by civilizations, and great apes, who are also impacted by modernity. There are more controversies than sureties. If great apes are any indication, life in the paleolithic was probably quite varied. Some tribes were probably warlike, others peaceful. In the meantime, anthropologists will continue to argue about the the significance bones with arrow wounds from 50,000 years ago, totally unaware that anti-civ activists have taken some isolated pop-sci fiction anthropology works and turned them into terroristic manifestos. That's not to say that I reject the idea that civilization has been a devil's bargain, but there is no way to know what we have lost and whether or not going back would make things better.
As for the book recs, I'm working on it :)
08/20/2011 - 13:54
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
- the idea that hunter-gatherers worked very little to support themselves and spent most of their time in leisure
- the idea of the Khoisan !Kung San peoples as examples of "Stone Age" foragers
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.
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