The Zookeeper's Dilemma
Imagine you are a zookeeper. A clear and pressing question about each animal is: What do they eat?
To maintain healthy animals, the first priority is to try to replicate what they eat in the wild. Feeding carnivorous lions rice cakes and herbivorous zebras fish cakes will lead to sick and eventually dead animals on both sides of the fence.
One of biggest-picture signs that something is not quite right today with human diets was expressed by Dr. Barry Groves (his lecture featured below). He pointed out that although we observe a great deal of chronic and degenerative illness among modern humans, this is largely unheard of among wild animals. However, it is seen among captive and domesticated animals, specifically, animals that are being fed the wrong food.
So what do humans eat?
Well, they eat a great many things. So what is the next question?
What do they eat in the wild?
With very few exceptions, humans today no longer live "in the wild" in any helpful sense, so this information is also not easily forthcoming. It is possible to investigate what modern human ancestors ate when they much more nearly did live much more "in the wild" during long, evolutionarily formative periods, say, 50,000–100,000 or more years ago.
Answers to another question would also help, and this one can be applied to moderns: What kinds of foods do they do best on?
Humans are able to eat a wide range of food and survive doing it, but what would be ideal? This shifts the emphasis to what foods humans thrive on indefinitely versus merely what they can manage to stay alive on for some years. This is a subject of extensive medical research. Sadly, much of it deeply flawed due to over-reliance on study designs that are inherently incapable of demonstrating causation. Such "studies," however, are far cheaper to fund and then use as the basis for getting another paper published.
One "evolutionary" influence on this field is therefore "publish or perish," rather than "arrive at the truest answers." Another is "follow the money," most of which traces back to pharmaceutical and "food" companies with something to sell.
Balancing a number of different lines of evidence, I have arrived at the view that humans are basically carnivores that can also survive on plant foods as a fall-back. They can survive on plant foods even for long periods, but cannot do so without suffering gradual degenerative harm. Feeding humans primarily—and especially only—plant foods causes them to become gradually malnourished, to sicken in a variety of ways, and to "fail to thrive."
This is commonly obscured for two reasons. First, the process of degeneration can take years and decades to progress. Second, moderns who move toward vegan diets often report feeling better, so it must be good, right?
On examination, however, they are quite often feeling better after moving away from from something rather specific—modern diets of processed foods. They are not moving away from an ancestral diet rich in fresh fatty meat. With some exceptions, many find their health deteriorating noticeably after a few years of veganism and are forced to quit.
Just because something is better than something else by some measures, such as feeling better or losing weight in the short term, this does not necessarily mean it is also ideal or even good. A typical vegan is both thin and sickly and will soon list up their many and varied health challenges, which they hope in vain that the next concentrated plant supplement might fix.
An excellent introduction to the argument in favor of the foregoing view is available in Dr. Barry Groves classic lecture: "Homo Carnivorus: What We Are Designed to Eat," embedded below. Many additional papers and lectures are linked in the resources page. An exciting new development is the "neuqalsmany" human carnivore study, organized by Dr. Shawn Baker and a community of zerocarb eaters interested in replacing vague speculation about the effects of a carnivorous diet with organized data about the health states of practitioners. Tens of thousands of modern humans have eaten meat exclusively, some for many years, each swearing by the dramatic health benefits of the change. This is the first time their health condition will be systematically assessed over a three-month survey trial, encompassing both old hands and those new to the approach.
If it is true that meat eating is the best human diet for health, another question follows. How could large-scale meat eating possibly work for a modern society? Tiny populations of paleo hunters could do it, but they were working with massive roaming herds, and many of those species went extinct! And isn't meat production already bad for animals and the environment already, even without being expanded still further? That is the impression given in the popular press as "settled science," so "settled" that no one even bothers to call it settled. Questioning it would be a pure heresy of the worst kind. So let us proceed to do so.
Although this belief has become quite popular, the balance of evidence I have seen indicates that it is severely mistaken. To explain this view, we must turn to some still different perspectives and sources, not directly related to nutrition.