The new documentary What the Health, which is currently streaming on Netflix, is spreading more rapidly than the fire that erupted as Bronn’s burning arrow ignited the Lannisters’ wildfire during the battle at Blackwater Bay. It acts like a very active microbe that’s rapidly multiplying and imbedding itself into the bodies of large numbers of people.
This wouldn’t have been a problem if it operated in a similar manner as a bacterium that has a good and fairly unproblematic relationship with humans, such as the lactic-acid producing critter Lactobacillus plantarum, which is found in many fermented foods. Unfortunately though, What the Health operates more like an opportunistic gut bug that suddenly grows out of control and completely takes over the compartment in which it finds itself.
Many opportunistic gut bugs are a natural part of the microbiota of their hosts and serve various important ecosystem functions. They don’t cause trouble, as long as they are kept in check by other members of the ecosystem that they are a part of. It’s only when they are allowed to proliferate uncontrollably that problems arise.
Just like such bacteria, What the Health serves many important and beneficial functions. However, sometimes, it acts up and expresses its darker nature, and towards the end of its runtime, it seems to go completely berserk. It acts like an opportunistic bacterium that lives in the gut of a person who starts taking an antibiotic drug that it is resistant to. As the peacekeeping microbes around it are exposed to the antibiotic substance and die out, it ceases the opportunity and rapidly expands its territory.
A Darwinian critique
What the Health has made it onto the screens of a lot of people’s TVs, and I get the impression that a lot of people trust the information that it presents, in part because it’s so popular and because they associate Netflix with high-quality productions. My goal with this critique is not to try and stop the spread of What the Health, but rather to put people on their guard. I think it’s extremely important that some of the issues that are discussed in the documentary, such as those related to sustainability, are given more attention; however, I would urge people to think twice before they follow all the dietary recommendations that the movie brings out into the public.
With that said, let’s get onto the critique…
What I meant when I said in the introduction that What the Health serves many beneficial functions is that it brings up a lot of important topics that should be more widely discussed. Moreover, it sheds light on a lot of issues that we – as a species – need to resolve. What the Health gets a lot of things right. Actually, I would say that it gets most things right.
The statements and recommendations of the “experts” that are given the opportunity to speak their mind in the movie are all over the place, in the sense that they are not homogenous with respects to their validity. They share some truths; however, they also express many thoughts and opinions that have absolutely no basis in reality.
I do agree with many of the fundamental statements the movie makes though. Among other things, I completely agree that our food production system is a mess, that milk is for babies, that most people would benefit from taking in more fiber, and that we should be concerned about the many toxins and drugs that are infused into our food supply. Despite this, I would say that the documentary is a pathogenic one; the reason being that I take great issue with the core idea it brings out to Netflix viewers all over the world; namely the idea that we would all be best off if we ate a diet that’s virtually devoid of animal source foods.
This idea, which will be the focus of this critique, conflicts with everything we know to be true about the evolution of the human diet, the compositional structure of man, and human biology. Towards the end of the movie, the male presenter makes the case that his “findings” and ideas pertaining to what constitutes a healthy human diet are consistent with the findings of evolutionary and biological research. This is simply not correct. What he’s actually doing is reconciling his ideas with evolutionary evidence that directly conflicts them by cherry-picking and distorting evidence.
I have nothing against him personally. I actually think he seems like a good guy. Also, he brings up many important points throughout the movie. With that said, many of his statements, as well as those of the experts he interviews, completely miss the mark. In particular the statements he makes towards the end of the movie hit far outside of their intended target.
He makes the absurd claim that humans are frugivores that do best on a diet that is exclusively composed of plant foods. In doing so, he reveals that he has little to not knowledge about evolutionary science, human evolution, or human anatomy. He seems to think that we are no different from our chimp cousins in that we too should fill our bellies with plenty of plant matter and little to no meat. Basically, he completely skips over what happened during the millions of years that span the time from when our ancestors ventured down from the trees in Africa to the present day.
What the evolutionary evidence really shows
It’s certainly true that our distant, tree-dwelling ancestors consumed a plant-based diet. However, it’s not true that the body of the modern man is designed for a vegan diet. A lot has happened since the days when our ape-like ancestors were sitting elevated above the ground devouring fresh fruits and the somewhat later time when early australopiths roamed the African savanna.
Several lines of evidence show that animal source foods started becoming an increasingly important part of the diets of our ancestors starting approximately 2-3 million years ago, roughly at the same time as when our genus, Homo, was “born” (1, 2, 3, 4, 5, 6). This idea, that meat was gradually incorporated into the diets of early members of Homo, is not only supported by various archeological findings (e.g., the discovery of stone tools used for cutting meat), but also by a big pile of research that has looked into the evolution and workings of the human body…
We’re morphologically adapted to eating a mix of both plants and animal source foods
Over time, our morphological configuration has changed, in part because our diet has changed. It’s well established that one of the reasons why members of Homo erectus, Homo habilis, and other now extinct hominin species grew such large brains is that they ate animal source foods (1, 2, 3, 4, 5, 6, 7, 8). Without animal source foods, our brains would never have gotten as big as they are.
The brain is a very hungry organ. It requires a lot of energy. It typically runs on glucose; however, it’s not built on glucose. Honey, tubers, and/or other carbohydrate-rich foods likely contributed to providing the fuel that was needed for the construction of the large human brain; however, it was animal source foods that did most of the labor and contributed the most to the construction process (1, 5, 6, 8). One of the things that make organ meats, eggs, fatty fish, and other animal source foods uniquely good at building big brains is their high content of long-chain fatty acids, which are incorporated into brain tissue (6, 8, 9). Not only do most plant foods contain very little fat, but the types of fats they contain are much less potent brain-building materials than those found in animal source foods (6, 8, 9).
The idea that we are adapted to eat a vegan diet also clashes with many other morphological features of the human body. Among other things, when compared to plant-eating mammals such as chimps, we have a small large intestine (7, 10). It’s well established that the human colon has gotten smaller throughout evolution, in large part because our ancestors transitioned over from eating a plant-heavy diet to a more energy-dense diet higher in animal source foods. Unlike wild plants, which typically contain quite a bit of fiber, a nutrient that is digested deep down in our bowels by gut bacteria, meat doesn’t contain much fermentable compounds. It is primarily digested in the upper parts of our digestive systems.
Not only is it unnecessary to have a large colon when one doesn’t eat massive amounts of fibrous plant matter every day, but it’s detrimental, in that it is energetically wasteful. The gut is not as hungry as the brain; however, it does consume quite a bit of energy. The reduction in the size of the large intestine was important in that it freed up energy that could be used on non-gut related processes, such as brain growth.
The truth about our teeth and stomach acid
As the presenter that follows us through What the Health talks about the structure and workings of the human body towards the end of the documentary, he makes some additional absurd and ignorant statements. Among other things, I get the impression that he, like some other proponents of vegan diets, is under the belief that meat putrefies in our guts. I’m not even going to comment on that idea, seeing as it’s so blatantly stupid and has absolutely no basis in nutritional science.
What I would like to comment on though is his statement that we humans are clearly not designed to eat meat, seeing as we have fairly small and unsharp teeth. It’s certainly true that our teeth look nothing like those of tigers, lions, and other animals that eat meat-heavy diets; however, that doesn’t mean that we are not adapted to eat meat. What eludes the presenter is that our teeth aren’t petite and flat because we evolved eating a vegan-type diet that one doesn’t need sharp, big teeth to degrade, but rather because we differ from other animals in that we know how to control fire and are highly capable of producing tools and weapons.
It’s certainly time-consuming and difficult for a man to kill and eat an animal if he doesn’t have any weapons or tools (e.g., sharp stones) at his disposal; however, it’s very much achievable if he does possess those things. If he also knows how to produce and control fire, the situation becomes even more manageable. Early Homo were likely not capable of producing fire at will; however, they did make stone tools. Also, later on, our ancestors also learned how to make and control fire. This was a crucial milestone in human evolution, in part because it boosted the digestibility and nutritional value of the human diet.
The presenter and the so-called experts we get to hear from in What the Health don’t just overlook the role animal source foods have played in shaping the human brain; the fact that our guts are morphologically organized differently from those of plant-eating primates such as gorillas and chimps; and the real reason why our teeth are nothing like those of flesh-eating carnivorous animals such as lions, but they also misrepresent the data pertaining to the workings of our digestive and metabolic systems. Among other things, the presenter makes the case that the characteristics of our stomach acid meet all “vegan criteria”. This is simply not true. Actually, the human stomach is very acidic (11). Research suggests that it has gotten more acidic over time (11), which is not surprising, seeing as our Paleolithic ancestors were scavengers and hunters who ate meat, which is a potential source of pathogens.
Our ancestors were certainly not vegan
The idea that we are not well-adapted to eat meat is further disputed by studies that have looked into the nutritional composition of hunter-gatherer diets. All hunter-gatherers eat meat (6, 12, 13). Actually, they take in a lot more protein than the typical westerner. A large analysis that included data from studies that have looked into the composition of various hunter-gatherer diets found that 73% of the hunter-gatherer societies included in the analysis derived more than 50% of their energy from animal foods and that the typical intake of protein was between 19 and 35% of total calories (13).
These numbers should be taken with a grain of salt, due in part to the fact that different researchers and explorers who’ve examined the nutritional behaviors of foragers have employed different analytical methods. With that said, this study, in conjunction with many other studies that have looked into the diets of both ancient and contemporary hunter-gatherers (2, 5, 14, 15), clearly prove that animal source foods are an essential part of the human diet. This is not to say that all hunter-gatherers eat a lot of meat (many don’t). All I’m trying to say is that the idea that we are genetically adapted to a vegan or vegetarian diet has absolutely no real scientific basis.
Some of the problems with veganism
Given that animal source foods have been an important part of the human diet for millions of years and that we are clearly genetically and morphologically adapted to eating a mixed diet composed of both meat and plants, it’s not surprising that the consumption of a purely plant based diet has been associated with multitudinous problems. So as to avoid making this article excessively long, I’m not going to get into all of them here. I would like to briefly bring up some important points though.
First of all, plants are a poor source of many important vitamins and minerals, including vitamin B12, zinc, vitamin A, and iron. Not only are plant foods low in these and many other micronutrients, but the bioavailability of many of the nutrients found in meat is much better than that of similar types of nutrient found in plants. For example, the vitamin A that’s found in meat is more “potent” than the beta-carotene (a precursor to vitamin A) that’s found in vegetables such as carrots.
Second, vegan and vegetarian diets tend to be very high in plant secondary metabolites and antinutrients, some of which can harm us (16, 17, 18). This is particularly true for diets that contain a lot of grains, which are problematic for a number of reasons.
Third, as most people know, animal source foods are superior to plants with respects to their amino acid profile. Why go through the trouble of trying to mix various plant foods and eating a lot of flatulence-inducing beans in order to attain a “sufficient” intake of protein when one can just eat eggs, grass-fed meats, and other delicious, protein-rich animal source foods?
Fourth, a vegan diet is by default a high-carbohydrate diet. Unlike what some of the so-called experts that are interviewed in What the Health claim, it’s not unproblematic to take in a lot of starch and sugars. In the environments in which our primal ancestors evolved, carbohydrate-rich foods were a scarcity. Chocolate, ice cream, and other highly processed, sugary foods were obviously nowhere to be found. Moreover, our preagricultural ancestors rarely ate grains. Hence, it’s not surprising that hunter-gatherer diets (both contemporary and ancient) are low in carbohydrate (13, 14, 15), or that diets that contain little or no grains and highly processed foods (e.g., Paleo-style diets) have been shown in several clinical trials to be superior to higher carbohydrate diets with respects to their impact on a variety of health markers (19, 20, 21, 22).
Last but not least, as discussed earlier, the human intestinal system is not designed to process huge quantities of plant matter. Animal source foods were an essential part of our Paleolithic ancestors’ diet in that it provided them with densely packed energy. Meat contains a lot more energy per gram than plant foods. In conjunction with the fact that our Paleolithic ancestors gradually understood how to control fire and cook food, this helps explain why the human brain is so big, why our digestive systems are sculpted the way they are, and why it can be very uncomfortable and difficult to eat a raw, vegan diet.
We need meat to thrive
It’s not surprising that all humans who live in a natural environment eat meat, seeing as a person who eats a vegan diet and doesn’t supplement quickly develops nutritional imbalances and deficiencies (e.g., vitamin B12 deficiency) (23). Moreover, hunter-gatherers and other humans who live in “the wild” don’t have unlimited access to fairly protein-rich plant foods. They largely rely on animal source foods for their protein, as well as for their omega-3.
It’s certainly possible to survive on a diet that contains very little animal source foods; however, I would argue that it’s not possible to thrive. A person who eats little to no animal source foods won’t necessarily express overt signs of nutritional deficiencies; however, that doesn’t mean he/she is necessarily healthy. It’s very important to distinguish between optimal nutrient consumption and “adequate” consumption (i.e., sufficient to avoid deficiencies).
For example, a normal-sized male who only takes in 50-60 grams of protein a day will certainly survive; however, he most likely won’t thrive, given that the protein intakes that supported the evolution of the complex human brain and body were markedly higher than that (5, 12). Protein differs in several respects from fat and carbohydrate. Among other things, it has a higher thermic value and possesses potent satiety-inducing properties (24, 25). A large body of evidence shows that many organisms, including humans, have a very strong appetite for protein-rich foods and that human protein requirements most likely have been significantly underestimated (26, 27, 28).
A person who eats a diet that is very low in high-quality protein is much more likely to take in more calories than he/she needs to maintain caloric balance than someone who eats a similar diet, but more high-quality protein (24, 27). The reason is simple: protein is an essential building block of the human body. Over evolutionary time, various apparatus that regulate our intake of protein-rich foods has been built into the human body. I know some plant eaters say that it’s not difficult to get “enough” protein from plant foods. I disagree with this statement. It’s undeniable that animal source foods are a superior source of protein to plant foods.
The fact that some people, including the athletes who are interviewed in What the Health, say they do well on a vegan diet obviously doesn’t qualify as evidence that veganism is healthy. Anecdotal reports are interesting, but they don’t qualify as real scientific evidence, at least not in my book. This obviously holds true regardless of whether the anecdotes come from vegans, Paleo dieters, or anyone else. One can’t exclude the possibility that the vegans and vegetarians who appear in What the Health would have felt even better and been in better health if they had eaten certain types of animal source foods.
I don’t doubt for a second that a plant-based diet composed of whole foods is a lot healthier than the typical western diet. However, it’s certainly not the optimal human diet. Even a plant eater who does supplement and carefully plans his meals so that they become as nutritionally good as possible will find it very difficult, if not impossible, to attain truly great health. The reason is simple: We evolved to eat meat!
What the Health lacks scientific validity; however, it does shed light on many important issues related to sustainability, human behavior, and the health of the planet
Before we wrap up I would like to point out again that the new Netflix documentary What the Health expresses many valid ideas and statements. I completely agree that we need to do something about our food production system, which is completely messed up. We need to acknowledge that the animals we derive our food from are no different from us humans in that they get sick and accumulate a lot of toxins if they are put into an environment they are not adapted to live in.
I fully agree that it’s not healthy to eat meat and other animal source foods derived from sick animals that have lived under confined, industrial conditions. I do not agree, however, with the statement that it’s unhealthy to eat meat, regardless of where the meat is sourced. Fish, eggs, organ meats, and other animal source foods have been a part of the human diet for a very long time – and should continue to be so.
It’s important that we distinguish between what’s optimal human health wise and what’s optimal sustainability wise. Veganism may be good for the planet; however, it’s not good for the body. When dietary recommendations for the public are to be designed, I would argue that we have to find a compromise between optimality and sustainability. The entire human population obviously can’t eat a protein-heavy Paleolithic diet; however, I would argue that it would be very unwise to tell people that they should eat no animal source foods at all.
The solution to the modern health crisis is not to get everyone to become vegan. In order to make some real headway towards combatting the many chronic diseases and health problems that run rampant in our world, we need to take better care of our planet, adjust our diets and lifestyles so they better match our genetics, and change the way we produce our food.
As consumers, we can vote with our dollars by buying meat, eggs, and seafood derived from animals that have had a good life. Politicians and government organizations can help push things in the right direction by putting money into sustainable food production and supporting farmers and companies that produce foods in an eco-friendly way.
The bottom line
What the Health sheds light on many important issues related to public health, food production, and sustainability. It gets a lot of things right. Unfortunately though, it also gets a lot of things wrong. At times, I found it pretty hard to watch, seeing as it, via the people and the concepts it features, presents a lot of misinformation. The thing I found most disturbing is that the documentary doesn’t have a strong, scientific backbone.
Natural selection, the guiding “force” that was largely responsible for shaping our bodies and nutritional requirements, is not even mentioned in the movie. All of “experts” the presenter puts his faith in are proponents of vegan-type diets who either overlook or misinterpret the evolutionary evidence pertaining to the role animal source foods have played – and continue to play – in the human diet.
Much of the “scientific” information that is presented in the documentary is cherry-picked and has no evolutionary basis. Everyone can find a study that seems to support their beliefs. In order to make some headway towards finding the truth, we can’t simple collect and blend together a random mix of scientific experiments. Rather, we need to examine how and why the world is put together the way it is and then proceed to use that information as our basis for creating testable hypotheses and deciphering modern research.
I by no means advocate that we should all be consuming a very meat heavy diet. The point I’m trying to make is not that we shouldn’t eat fruits, vegetables, and other plant foods (we definitely should), but rather that we are genetically adapted to eating a mix of both plants and animal foods. The idea that we are designed to eat a vegan diet goes against everything we know to be true about human biology and human evolution, including the evolution of the human diet.