The central tenet of the Paleolithic diet (also known as the Primal diet, as popularized by Mark Sisson) is that, for a very long time, humans ate a high-meat diet, and through the process of Biological Evolution, we became adapted to it.  So, we have to keep doing it because it’s, well, our thing.

But, are we really well-adapted to it?  I think there are good reasons to think that humans are not very well-adapted to a high-meat diet, that we are, in fact, mal-adapted to it.

Consider first: appendicitis. It is amazing that even today, there is little information disclosed about the causes of appendicitis. Supposedly, a person can be perfectly healthy- normal in every way- and then suddenly come down with life-threatening, acute appendicitis.  “What a tough break, what a piece of bad luck that he should come down with appendicitis. He was the picture of health!”  But, doesn’t it stand to reason that, regardless of how he looked on the outside, and regardless of how he felt, that there must have been something very morbid and abnormal on the inside for such a thing to happen?

Appendicitis is thought to be caused by an obstruction of the lumen of the appendix by hard, compacted stool.  Sometimes, we hear that tomato seeds or other seeds are to blame, but that’s ridiculous. My goodness, if tomato seeds could cause appendicitis, we’d all be afflicted.  The fact is that appendicitis is very much a meat-eater’s disease. Multiple studies have shown it- one being the Oxford Vegetarian Study as reported in the American Journal of Clinical Nutrition, September 1999. Plant fiber protects against appendicitis, and the more plant fiber you eat, the more protected you are.  Another reference is:  Emergency Appendectomy and Meat Consumption in the UK, as reported in the Journal of Epidemiology and Community Health, December 1995. The incidence of appendicitis has actually declined, and that’s because eating plant foods, such as green salad, has become more commonplace. What I have observed is that eating an inordinately large portion of meat all at once can trigger appendicitis- especially in someone who is not used to it. Many times, for instance, I have heard about people going to a barbecue and pigging out and then coming down with appendicitis.

Some mammals have true appendices just like ours, while others have ends to their cecums that are different but still appendix-like. So, why is it that humans are the only ones inclined to develop appendicitis? And why is it that cats, and other pure carnivores, can eat 100% meat diets without developing appendicitis, or anything like it that is comparable to their anatomy and physiology, while humans succumb? I would argue that it’s because cats are adapted to a high-meat diet, while humans are not adapted to it.

Likewise, gallstones and gall bladder disease happen much less often among vegetarians.  There is an attitude in Medicine that it’s time to get your gall bladder out when you’ve reached a certain age.  That, of course, is nonsense. You should be able to go your whole life without having gall bladder problems. You shouldn’t hear a peep out of your gall bladder your whole life. You shouldn’t even know that your gall bladder exists- except for reading about it in a book.

Gallstones are made of cholesterol, and they form when the bile becomes super-saturated with cholesterol. And that comes from a high-meat diet. Many studies have confirmed it. Here’s one: Risk Factors for Gallstones in a Thai population, as reported in the Journal of Epidemiology, April 2009. There are many like it. And likewise, true carnivores can eat a 100% meat diet without corrupting their gallbladders. Polar bears live on seal, particularly seal fat, yet, they don’t get gall bladder disease from it. They, unlike us, are truly adapted to it.

Ditto for kidney stones. Again, lots of studies. Here’s a quote from “Kidney Calculi: Is diet a trigger?” from the German Medical Journal, March 2000: “Epidemiological studies confirm that a diet rich in meat protein carries an increased risk for forming urinary tract stones.”  And again, do lions and tigers get kidney stones? Of course not. They’re not like us. Or, I should say: we’re not like them.

Gouty arthritis arises from the high purine content of meat which elevates uric acid in the blood. I’m not even going to give you a citation because it’s been known for centuries that heavy meat-eating triggers gout. That’s why they called gout the “disease of kings” because they were the only ones rich enough to afford to be able to eat the amounts of meat necessary to cause gout. Yet, in contrast, natural carnivores can clear uric acid from their blood no matter how much meat they eat.  They’re adapted to it; we’re not.

Of course, I could also bring up cancer and heart disease and their correlations with meat-eating, but I will not because most people have heard about that; paleos are aware of it, and they do try to address it. And also please know that my purpose in addressing this whole issue is to not argue for radical vegetarianism.  My purpose is to argue for a plant-based diet, which means, regardless of how you feel about hunting animals for food or raising them for food, that, in pure self-interest, you should eat primarily plant foods simply because it is in your best health interest to do so.

So, let’s frame this into a question for next year’s Ancestral Health Conference:

Heart disease and cancer have been correlated with a high-meat diet, and paleos have, at least, tried to address those issues. But what about other diseases, such as appendicitis, gall bladder disease, kidney stones, kidney failure, gout, inflammatory bowel disease, and others which have been strongly linked to meat consumption? Does it not challenge the assumption that humans are, through Biological Evolution, well-adapted to a high-meat diet?