Straight Poop on the Paleo Diet

This Science News’ story, Neanderthals reveal their diet with oldest excrement caught my eye. The shifting and mixed opinion on diets finally drove me in the late 70’s to look outside the box and seek insight from nature for clues to the optimum diet for our species.

I spent weeks at the central library in Stockholm, Sweden, digging up all the information I could find. Knowing that we are one of the four great apes, I decided to research the diets of our three brother apes, orangutans, gorillas, and chimpanzees. As I recall, they all forage from a selection of around 200 different plant species.

While the first two are utter vegetarian, Jane Goodall discovered a slight difference in the chimpanzee diet. Come to find out, they eat insects and even larger animals that they have hunted and killed themselves. However, the vast bulk (98%) is made up of a wide variety of plant foods including fruits, seeds, nuts, leaves and flowers. Like us, they are omnivores. (see, Biology & Habitat).

I’ve always trusted nature’s empirical example more than ‘expert human opinion’. This led me to conclude that we great apes evolved to eat a diet composed largely of fresh vegetable matter. I made up a chart to see how each of three ‘pure diets’ would fair vis-à-vis our core vitamin and energy (caloric) requirements.  The chart compares three simple diets: 100% Meat, 100% Grain and 100% Vegi.

These results made complete sense, although given modern circumstances and desires it certainly isn’t practical as our sole diet. Nevertheless, the further back we look in “Genus Homo” history (our branch of the great ape family tree), the more vegetable matter our diet turns out to contain. It was only through advances in hunting tools beginning about 100,000 years ago, that our diet became much more meat oriented. See Science News’ Going Coastal: Sea cave yields ancient signs of modern behavior. Then, with the onset of the agricultural revolution just 10,000 years ago, our diet became overwhelmingly grain oriented.

Study the three diets above closely. You’ll see that if you were limited to one of them exclusively, the vegetable diet is the only one upon which a modern human could actually survive. If the meat diet included the whole animal, including stomach contents, it would at least permit survival. See Science News’ Neanderthals ate stomach goop, and you can too ⁽¹⁾. While perhaps not practicable to eat vegetables exclusively, it tells me to eat as much fresh vegetable matter as possible.

The Popular Paleodiet

This Science News’ story, Neanderthals reveal their diet with oldest excrement, supports some basic aspects of the so-called paleodiet popular today. As usual with most things humans do, we tend to go to extremes. I imagine our ability to think causes this slide to extremes. This must be one symptom of our “disease”, i.e. Realizing I don’t know is better; not knowing this knowing is disease. This also helps explain why, in our search for ‘answers’, we walk right past the obvious.

Here is a short excerpt from the ‘oldest excrement‘ article that speaks to some of this:

As for what was on the Neanderthal dinner plate, there’s been plenty of controversy. Long thought to be mainly top-level carnivores, the emerging picture is that Neanderthals gathered and even cooked a range of plants. Tiny plant fossils turned up in some of their massive tartar buildup, though as I wrote last year anthropologists have also suggested some of the plant material might have come from Neanderthals eating herbivores, including their plant-filled stomach contents.

Much hay has also been made about translating what our ancestors ate into a rational healthy diet for today. (For an interesting overview of some of the recent research and the battle over the ills of carbs versus fats, see this recent article in Aeon.) The upshot, as I see it, is that the tide is rolling against the low-fat diets of the past couple decades and toward blaming more of our dietary woes on carbohydrates, especially the refined and processed varieties like those that make up my beloved croissants. Green vegetables, the one thing it’s hard to get people to eat if they have lots of choices, remain beyond reproach.

Those who consider themselves to be paleodieters of one variety or another (and there are many varieties) generally hold as a premise the human body has been poorly equipped by our evolutionary ancestors to handle high loads of carbs. In some cases paleodieters even eschew anything that a perceived Paleo Man would not have had access to. If our Neanderthal cousins at El Salt are any indication, this means eating a lot of cooked deer and goat. I certainly don’t know what the optimal human diet is at this point, but I will quote Sistiaga: “We are not living the way they were.”

And I would add, they were not living the way their ancestors were. The Neanderthals were eating their own iteration of junk food, although, nothing as junky as modern humans are capable of eating.

⁽¹⁾ Here is a excerpt from this ‘stomach goop‘ article.

But now anthropologists Laura Buck and Chris Stringer of London’s Natural History Museum suggest in Quaternary Science Reviews that instead, Neanderthals may have picked up some of these plants by eating the stomach contents of their prey. That would explain the presence of plants with no obvious nutritional value to hominids.

They would hardly be unique. Consider explorer Fridtjof Nansen’s 1893 description of Inuit eating reindeer chyme, as quoted by Buck and Stringer:

“It has undergone a sort of stewing in the process of semi-digestion, while the gastric juice provides a somewhat sharp and aromatic sauce. Many will no doubt make a wry face at the thought of this dish, but they really need not do so. I have tasted it, and found it not uneatable, though somewhat sour, like fermented milk.”

The sourness would come from stomach acid; the pH of human chyme is around 2, similar to lemon juice. In other words, perfectly edible.

Only in today’s warped food scene could people refuse to eat anything but boneless, skinless chicken breasts. The Inuit traditionally ate reindeer chyme because it was a source of plant matter, a rare commodity in their environment. Eating nothing but protein can be toxic, so letting the reindeer do the hard work of finding all the most tender mosses and lichens is pretty smart. The KhoeSan eat porcupine stomach because of the animals’ diet of medicinal plants.

For a more complete review of the Neanderthal diet, see Quaternary Science Reviews’ Having the stomach for it: a contribution to Neanderthal diets?