The “Paleo Diet”: Real or Fad?
Zeal for “healthy eating” is almost on par with religion and politics for many people. Take the Paleo diet as an example: the Paleo diet is one of America’s fastest growing dietary programs, yet how scientifically based is it? The Paleo diet is based on the idea of abandoning modern agricultural diets because they make us ill; instead we should eat like our Paleolithic ancestors from more than 10,000 years ago. Intuitively, it makes sense to harken back to our ancestors for answers to our most difficult chronic disease-related questions, like digestive disorders, obesity, diabetes type 2, and heart disease. However, what if the true diet of our Paleolithic ancestors is virtually non-existent today due to Neolithic farming practices that long ago altered vegetables, fruits, seeds, and nuts, and our common meat sources like beef, poultry, and eggs? Is the Paleo diet nothing more than a modified Neolithic, farm-based diet?
Dr. Christina Warinner is an Archeologist at the University of Oklahoma and the University of Zurich’s Centre for Evolutionary Medicine. Her area of specialization is health and dietary histories of ancient peoples using bone biochemistry and ancient DNA. Through examination of the scientific evidence, Dr. Warinner de-mystifies several myths promoted by Paleo diet enthusiasts due to a lack of basis in archeological reality.
Myth #1: Paleolithic people evolved to eat meat and consumed large quantities of it.
Humans have no known anatomical, physiological, or genetic adaptations to meat consumption, yet humans have many adaptations to plant consumption. For example, carnivores make their own vitamin C. Since vitamin C is found in plants, carnivores must synthesize their own vitamin C since they do not consume plants. Humans cannot make their own vitamin C and must consume plants in order to acquire this essential nutrient. Humans also have longer digestive tracks than carnivores in order to digest plant matter and have molars to shred fibrous plants. On the other hand, humans do not possess carnassials, which are specialized teeth used to shred meat. While humans have some genetic adaptations to animal consumption, it’s limited to consuming milk not meat.
Further, the primary sources of meat today are from domestic cattle with much higher fat content than the lean, small game that would have been eaten by Paleolithic people. Paleolithic people ate organ meat and bone marrow, two important sources of nutrients. Native peoples in the Arctic ate a lot of meat because of long periods where plant matter wasn’t available; however, people in temperate and tropical regions ate plants as a large portion of their diets.
Myth #2: Paleolithic people did not eat whole grains or legumes.
Stone tool evidence from 30,000 years (20,000 years before the agricultural age) includes tools similar to mortar and pestles to grind up seeds and grains. Fossilized dental plaque allows recovery of plant microfossils and other remains today. Myriad plant remains have been found in the dental calculus of Paleolithic people and includes grains (e.g., barley), legumes, and tubers.
Myth #3: Foods listed under the Paleo diet are what Paleolithic people ate.
In charts of any Paleo diet book, images are shown of domesticated produce as a part of a Paleo diet that were radically altered from their wild counterparts to suit human needs such as increasing size, decreasing toughness, toxin load, latex, spines and seed content. In other words, produce in any grocery store or farm stand is the product of agricultural domestication dating back to the Neolithic transition. Vegetables, fruits, nuts and berries listed as “Paleo foods” are human inventions.
Food quantities for Paleolithic peoples were also much smaller overall. For example, a large amount of wild broccoli would have been necessary to approximate our domestic variety. Plants collected were tough, woody and fibrous and contained toxins along with beneficial phytochemicals. Meat sources were very lean and included eating the organs and marrow. It is virtually impossible for everyone to eat a truly Paleolithic diet based on foraging – the global population is simply too large.
Myth #4: There is one singular Paleo diet.
When referring to Paleolithic diets, it is important to speak of them in the plural. Throughout the world, Paleolithic diets were widely variable based on climate, region, locally available foods and season. When more plants were available, more were eaten (e.g., temperate and tropical regions); when fewer plants were available, fewer were eaten (e.g., Arctic region). Seeds and fruits were available during different times in the year; and herds migrate and fish spawn on seasonal cycles. People had to move from resource patch to resource patch with periods of high mobility and sometimes over long distances.
What can we learn from our Paleolithic ancestors?
Eating a diet rich in species diversity is important for consuming the vital nutrients we require for healthy life. Today’s trends in American diets are in the opposite direction because nearly all processed foods contain wheat, soy, or corn. Additionally, nearly all non-organic soy and corn is genetically modified.
We evolved to eat fresh foods when they are in season with their highest nutritional content.
We evolved to eat whole foods in their complete package with fiber and roughage. By decoupling whole food from the nutrients inside, we trick our bodies and override the mechanisms that evolved to signal fullness and satiation. For example, one 34 oz soda is equivalent to 8.5 feet of sugar cane. While no Paleolithic person could consume that much sugar cane, the same sugar content can now be consumed in 20 minutes.