Debunking the Paleo Diet: A Wolf’s Eye View
Sorry I did not get to this sooner, both for you AND for me. I’ve received a truckload of emails, tweets, and Facebook questions asking for my opinion on the Tedx talk by Prof. Christina Warinner titled “Debunking the Paleo Diet.” My response to many folks has been “I’m getting to it”, and “Did you watch the entire thing?” Far, far too many people did not bother to watch the entire piece. 10 paleo demerits. Whether we are talking about a paper, a blog post, or a video piece like this, if you are going to ask someone else to take the time to give some analysis on a topic, it’s important you do as much homework as you can. There will be circumstances in which material may be overly technical, and you will rely on someone like me the same way I rely on some tech/computer writers. No harm with that, we can’t all be experts at everything. But, it’s important to put some skull-sweat into stuff like this, both for your intersects, and to keep this ancestral health idea honest and evolving. So, if you have not watched the WHOLE video, get to it:
Ok, so the way I’m going to tackle this is work my way through the talk, and give you time points where I will comment on Prof. Warinner’s video, good, bad, or indifferent. I’ll put the time point in the video followed by the topic, if easy to discern, then my thoughts.
0:25- The Paleo Diet is one of America’s fastest growing diet fads.
This is possibly nit-picky on my part, but getting a PhD from Harvard, I think Prof. Warinner picked “fad” in lieu of “trend” for a bit more…”pop.” It’s kind of a bummer, as right out of the gate one is feeling a bit set upon if you are rooting for an Evolution based dietary template to make some headway into academia.
0:55- This idea was really started in the 1970’s
The idea that we see a change in health from the transition out of the HG lifeway and into agriculture is a good bit older than the 1970’s, and has “evolved” in isolation in quite a number of locations. I detailed one such example here.
A medical doctor, Roman Shatin MD, connected most of the dots related to celiac, autoimmunity, and grain intolerance in the early 1960’s. Please DO read that whole post including the two attached papers by Dr. Shatin. It is fascinating how much he knew, how long ago he knew it…and the fact we still managed to lose that information for over 50 years. There are plenty of older examples such as Weston A. Price’s work, as well as this book, Primitive Man and His Food, from 1952 (a B-day gift from The Kraken, no less).
Perhaps Prof. Warinner is looking mainly at American pop-culture diet books as her reference here, but the idea of a “Paleo Diet” being beneficial to health has been around quite a long time. I’d wager it’s only been since the advent of the internet that we’ve been able to offer up the greasy used-car-salesman’s pitch of “try it, see how you do” to get enough people to really get some traction and buy-in.
1:22 The Paleo Diet does seem primarily targeted at men.
I put “paleo diet” into google, clicked on “images” and got the following photo:
If you scroll down a bit you certainly see some shirtless males (which I think It’s tough to say WHO that is targeted to…I think gals generally like seeing shirtless guys, assuming they are so inclined) but this feels a bit…dishonest. Not sure how/where Prof. Warinner came upon the images she cites, but if I refine the search and look for “Paleo Diet Before and After” (the first suggestion from google) we get this spread:
Out of 12 people, two are males. In the diet game the most powerful tool we have is the before/after photo and the vast majority of what exists is of…women. Prof. Hamilton Stapell of SUNY New paltz recently did a survey of “Paleo Land” and 56% of the respondents were women. From a “debunking” standpoint I can’t help but feel like this is an attempt to paint the whole PD concept as a marginal, wacky, male oriented Flintstone revival, with nothing to actually back that position up. Said another way, it does not get the conversation off on a good tone.
1:40- Four concepts of the “paleo diet”
1- Agricultural diets of today make us chronically ill.
2- We need to eat more like our ancestors of 10,000 years ago.
3-We know what these diets were like and they had “a lot of meat.”
4-If we emulate this ancient diet it will improve our health and make us live longer.
Prof. Warinner lays these points out, then takes each point to task.
3:18-Humans have no known anatomical, physiological or genetic adaptations to meat consumption.
Anatomical adaptations: Prof. Warinner Makes the point we do not have adaptations typical of most carnivores, like specific dentition (I’ll get to the digestive tract in a moment). I find this a bit problematic, as our meat eating appears to have developed in lock-step with the technologies of tool use and fire. Richard Wrangham of Harvard makes the point humans “pre-digest” their food outside the body by cooking, cutting, grinding, and processing. Humans have no “anatomical adaptations” to the cold (generally…there is a tendency for cold living people to become more barrel chested, shorter limbed, thus creating less surface area and conserving heat…Neanderthals showed this same tendency) yet we have populated areas of extreme cold by the use of technology: clothing manufacture, insulated structures to live in and again, fire use. The omission on the part of Prof. Warinner on this point of technology driving various aspects of human evolution is really troubling for me. Clearly she must be aware of this, but for some reason ignores this point entirely.
GI Morphology: Humans are clearly opportunistic omnivores, our gastrointestinal physiology is intermediate to that of an herbivore (multi-segmented, fermentative stomachs, regurgitation and re-chewing of food in fore-gut herbivores, reliance on bacterial fermentation and the production of volatile organic acids (for fat production no less!) in hind-gut herbivores) and that of a carnivore (short, relatively smooth intestines lacking haustrations for fermentation).
Prof. Warinner also fails to mention that the actual development of not just our species, but the species immediately preceding our own, was characterized by a shift away from a largely fermentative diet in favor of a more concentrated diet including meat. This is the backbone of the Expensive Tissue Hypothesis in which pre-human ancestors traded gut size for increasing brain size. Why no mention of any of this?
Shifting away from meat for a moment, humans have many, many more copies of the genes which code for amylase production (necessary for starch digestion) than do chimps. We also see a distribution of this gene frequency trending with populations who have historically eaten more starch. Interestingly however, without cooking, starch is about 30% less digestible and the utility of eating starch from an optimum foraging strategy standpoint occurs. What is significant in all this is that cooking/technology clearly played a role in the genetic adaptations involved in starch digestion, but again, no mention of any of these big-picture concepts like optimum foraging strategy.
Some degree of “meat” consumption appears to be part of seemingly all primate diets. Chimps actually hunt, gorillas eat some termites (and perhaps a few of their smaller cousins). Heck, even deer appear to occasionally eat meat. The basic machinery for meat consumption is inherent in all primates. Humans are interesting in that they do show a conditionally essential need for Taurine, a nutrient that IS essential for carnivores. So, humans do show a tendency towards carnivory on both a physiologic AND genetic levels with this adaptation.
Prof. Wariner concludes this section by conceding that clearly humans ate meat. At high latitudes they consumed much more, equatorial regions saw much less. She also made the point early humans ate the whole animal, including brain and bone marrow. I cannot help but wonder exactly WHICH books or research papers she has read on this topic? From Boyd Eaton, to Loren Cordain, to myself (and a host of other folks) we have talked about the seasonality/locality variability of food intake. We have talked about eating the whole animal…I’m just confused by her adding an after-thought to what has been the foundation of a “Paleo Diet” since at least 1985, and Dr. Eaton’s paper which appeared in the New England journal of Medicine. And all this supposedly “debunking” human meat consumption! If anything, this is a remarkable statement that humans did NOT evolve as vegetarians…why no angst towards that fad diet? Perplexing.
The bottom line on this piece: Prof. Warinner seems reticent to acknowledge the primary literature on this topic, although she gives airplay to exactly what the primary literature states, but sadly, only as an afterthought. I get the sense she has gravitated towards the Low-Carb side of this discussion exclusively, and she clearly is not a fan of “RED MEAT!” as she says it a remarkable number of times in a very brief interval. She mentions the leanness of wild meat, contrasting this with modern grain fed meat, citing the PHOTO in her talk as support for what paleo is advocating. If you’ve been around the scene any length of time, you know we talk about all these issues.
Prof. Warinner’s analysis of the limitations of stable isotopic readings is VERY interesting and important. This is something that has been used to hang many a hat on human meat consumption, and certainly the issues with this technique need to be understood. That said, we also have clear indication of mega fauna die-off which appears to be driven in large part by human predation, although there are wrinkles even within this story.
8:36-Paleolithic people did not eat grains nor legumes
There are some very interesting developments with dental plaque analysis indicating consumption of tubers, grains, and legumes much earlier than was previously thought. Optimum foraging strategy would indicate almost everything that could be eaten, was eaten, at least occasionally. But what provided the bulk of the diet? What was the significance of shifting from a foraging lifeway to a grain based lifeway? Why no commentary on this?
This is a common story in anthropology/archeology, in that the dates for just about everything one cares to consider keep getting pushed back. Fire use was once thought to be only a few thousand years old, now that date may be 1.5 million years. As to the grain/legume consumption itself, it still begs the questions of what is really healthy to eat, particularly as a preponderance of calories? A bit later Prof. Warinner describes the diet of a HG group from central Mexico which includes some beans…and a whole bunch of other stuff. That all seems fine, healthy, and non-controversial to me.
9:54-14:00 the foods portrayed as being “Paleo” are all a product of farming and agriculture.
This is a FANTASTIC section. It is true, unless you do significant foraging on your own, most of what we consume has been “Luther Burbanked” into large, tasty, low toxin-load fruits and veggies. Everything in nature has something that wants to eat it, which is why we see horns, thorns, claws, quills, and poison. Cattle have been bred to be relatively docile, have small or no horns, and to accrete body fat efficiently. Our fruits are generally large, tasty, and low in bitter tasting toxins. Prof. Cordain addressed all these issues in his paper “The Nutritional Characteristics of a Contemporary Diet based on Paleolithic Food Groups” and made recommendations that try to best emulate what was available to our ancestors. What is intriguing is these modern foods are still MUCH more nutritious than the grain bases of most modern diets, as is evidenced by Mat Lalonde’s work on nutrient density. If we shift gears and use the Registered Dietician’s criteria of “nutrient density” (the most vitamins, minerals/calorie) our “paleo foods”, be they legitimately ancient or modern cultivars, “win.” Add to this allergenic/immunogenic potential, and it’s a landslide in favor of “paleo.”
14:09 There is no one “Paleo Diet.”
True, and this has again been addressed by Prof. Cordain. Seasonality, locality, variability has ALWAYS been part of this discussion. This is an interesting refrain that was part of the US News critique of paleo, and just never seems to die. Perhaps it’s because none of these folks are actually reading books/papers on the topic?
This is a great description of what HG’s of central Mexico ate, and the fact they moved with the seasons and availability of food. Beautiful, very interesting piece…I wish we had an hour on this alone.
15:30-ish to end
This is a simply OUTSTANDING section. Diversity of food sources, locality, and understanding of the neuro-regulation of appetite, changes in the gut biome…how easy it is to eat a caloric level that is completely inappropriate with our genetics, eat the whole animal…
This last section is why I asked folks “did you watch the WHOLE thing?” The front end of the video has some stuff that can get your ears forward a bit, but the final sections are really fantastic.
Yes, I think Prof. Warinner seems to have focused on the popular media interpretations of paleo. It’s painful she did not reference original work by folks like Loren Cordain, Boyd Eaton, Staffan Lindeberg, etc, as they did/do address her commentary about “one paleo diet”, “our modern foods are not the same as 10,000 years ago”, etc. But ultimately, she, as a scientist researching this stuff, made the final point that we have much to learn from anthropology and evolutionary medicine. Indeed we do, and bravo to her for that.
When I was wrapping up my biochem undergrad (around 1997) a paradigm at that time was called the “Central dogma of biology” which was “one gene, one protein.” When the various genome projects got underway there was an expectation of most critters having far more genes than what we in fact find. The assumption that every gene codes for only one protein has been overturned. Post translational modifications and squirrelly activity on the part of RNA paints a very different picture. Did genetics and biochemistry crumble under this? No. We learned and moved on.
Certain assumptions have been and will be made about the ancestral diet and health. Some will prove to be accurate, some not. It is perhaps unfortunate, as I have said many times, that “Paleo Diet” was chosen instead of “Evolutionary Nutrition.” But even this is simply an artifact of looking at the literature produced by the predecessors of Prof. Warinner who made the observation that our HG ancestors (and contemporarily studied HG’s) appear to be largely free from the disease of modernity, and that PERHAPS eating more in this fashion might confer health benefits. What I have sensed from the anthropology community is an almost…annoyance that upstarts from outside that Guild have the temerity to talk about this stuff and try to apply it in an actionable way. Well, someone needs to! Prof. Warinner does good service to this concept at the end of her talk.
If I could wave a magic wand I’d hope for a bit less prickliness on the part of the medical anthropology community on this topic. Even more so, I’d hope that these folks could realize they, not our current medical system, have the insights on how to fix what ails us. If we could get them to understand just how important their understanding of the past is, we might have a much better future.
I’ve gotta say, the “RED MEAT” piece to this is pretty annoying as I re-read the post and re-watch the video. Initially this was annoying as the PD has always recommended a variety of protein sources and Prof. Warinner painted that story in a very self serving way. But when we add to this her final comments about “feeding the world” (paleo will apparently not work) and overlay this with work by the Savory Institute it is again troubling what Academia is able to claim and suffer no internal push-back, simply because it comports with the assumptions of that group.
We’ve been in contact with the Savory Institute and you should see some exciting collaboration in the near future.