Paleopathology and the Origins of the Paleo Diet

“Blood-vessel disease was common (among the ancient Egyptians), contrary to assumptions that it arises from urban stress and a modern high-fat diet,” Dr. Michael Eades, MD, reads aloud to the audience at the CrossFit Health Conference on Aug. 1, 2018. Eades is a well-known physician and author of several books about the science behind low-carb diets, but this quote from Arno Karlen’s book Napoleon’s Glands brought to mind knowledge from a previous career path, when he was a college student interested in Egyptology.

Eades had researched the dynastic Egyptians’ lifestyle and knew they had eaten a wheat-based diet. The statement he read in Karlen’s book, he says, “electrified” him. He recalls waiting in anticipation for the library to open the next morning so he could perform additional research on the ancient Egyptian diet and its potential relation to cardiovascular disease (CVD). In this presentation, Eades shares some of the outcomes of that research, taking his audience “on a journey through the anthropological literature and what that means in terms of ‘off the carbs.’”

Eades discusses the research of Max Kleiber, who in the first half of the 20th century “was obsessed with one thing: He was trying to come up with an equation that correlated metabolic rate to body size.” In 1947, Kleiber published an article articulating what would become known as “Kleiber’s law,” which Eades explains suggests, “If you know the body mass (of an animal), you know what the metabolic rate is.”

Kleiber’s research influenced Leslie Aiello’s development of the expensive tissue hypothesis, which suggests that if metabolic rate is fixed, humans and other primates have evolved differently such that humans have more brain tissue and other primates have more gut tissue. Eades compares the skeletal anatomy of Homo sapiens and Australopithecus to demonstrate humans have less room for gut volume and more for brain volume. “The reason these herbivores have such large bellies is because they eat plants, and plants are not very nutritionally dense,” Eades explains. Some argue cranial capacity in Homo sapiens increased over time, and the increase in brain power made us capable of hunting, thus enabling a shift toward a more carnivorous diet. Eades reverses the causative part of this claim: “We didn’t evolve to eat meat. We evolved because we ate meat,” he argues.

Eades’ research into the Egyptian diet question also led him to stable isotope analysis, a method of studying ancient people’s remains that provides insight into what they ate. The study of carbon (C-13 and C-14) and nitrogen isotopes (N-14 and N-15) helps scientists ascertain the nutrient sources of ancient humans and animals. “When herbivores eat plants, they concentrate the N-15 by about 5-8% in their collagen, so if a collagen sample contains a delta N-15 level greater by 7% than the local flora, then the animal is an herbivore,” Eades explains. By examining N-15 concentrations in Pleistocene-era remains, scientists have determined that neanderthals were not only meat eaters but that they ate herbivores and other fellow meat eaters.

Later remains of human ancestors reveal a huge health disparity developed between ancient agriculturists and hunter-gatherers, Eades notes. Hunter-gatherers ate a low-carb diet; farmers ate a low-protein, high-carb diet containing a lot of corn, beans, and pumpkin. Skeletons of the agriculturists reveal they suffered from portico hyperostosis and cribra orbitalia, a painful condition that signals iron deficiency anemia, as well as enamel hypoplasia. Eades claims, “When agriculture came along, health went to hell in a handbasket.” He cites a quote from Jared Diamond’s Guns, Germs and Steel for corroboration: “The adoption of agriculture, supposedly our most decisive step toward a better life, was in many ways a catastrophe from which we have never recovered.”

Eades then brings all this knowledge to bear on his analysis of the dietary factors that may have contributed to the health problems found in ancient Egyptian mummies. Sir Marc Armand Ruffer, an English bacteriologist and pathologist, performed autopsies on mummies in Egypt at the turn of the 20th century and found CVD was widespread among the ancient Egyptians. Eades notes the Ebers papyrus, a medical text from 1550 B.C., says, “If thou examinest a man for illness in his cardia and he has pains in his arms and in his breast and in one side of his cardia … it is death threatening him.” This speaks to how common CVD was among the Egyptians, and Eades argues the ubiquity of the disease was caused by their dietary staple. Stable isotope analysis reveals the ancient Egyptians consumed a high-carbohydrate diet, deriving most of their nutrients from whole grain bread.

The ancient Egyptian diet, Eades says with wry humor, is “a modern nutritionist’s nirvana,” because “the ancient Egyptians ate a diet that almost any nutritionist would tell us to eat now to avoid getting all the things that the Egyptians got.”

“So if you look at all the data out there,” Eades concludes, “you look at the metabolic constraints, the Kleiber line, the expensive tissue hypothesis, you look at the stable isotope data, you look at the hunter-versus-farmer data, you look at the ancient Egyptian data, you look at the modern RCTs, and it’s pretty clear that ‘off the carbs’ is the way to be.”

To read a full transcription of the presentation, click here.