We evolved eating huge amounts of plants. It’s estimated that 200,000 years ago we got 600mg of vitamin C a day. That’s the amount of vitamin C found in 10 oranges. Every day we appear to have consumed the amount of vitamin E found in 2 cups of nuts, the amount of fiber found in 12 bowls of oatmeal, and the amount of calcium found in 5 cups of collard greens. They weren’t milking mammoths–that came from all the wild greens they foraged.
As I note in the above NutritionFacts.org video pick, we were exposed to such a quantity of whole healthy plant foods that we, as a species, lost our ability to make vitamin C. We still actually have the vitamin C gene in our DNA, but our bodies presumably just junked it because we were getting such massive daily doses that it wasn’t worth maintaining it. The problems occur when you take our evolutionary heritage, fine-tuned over the millennia, and plop it down into meat and potato chip country.
Advocates of the so-called Paleo diet are certainly right in railing against refined and processed junk, but may just use it as an excuse to eat loads of meat that bears little resemblance to flesh of prehistoric wild animals. The contaminant issue alone is compelling reason to eat as low as possible on the food chain. As I show in the video, the journal of the American Meat Science Association recently published a review cataloging the laundry list: arsenic, mercury, lead, cadmium, polycyclic aromatic hydrocarbons, preservatives, and veterinary drugs such as antibiotic residues. Given what’s now in fish, for example, “it would be impossible to follow the Paleolithic diet while avoiding the risks associated with consuming mercury in amounts in excess of the suggested EPA threshold.”
The “paleo” diet patients I saw in my practice weren’t consuming weeds and eating in excess of 100 grams of fiber a day. They were eating burgers, not bugs. As concluded in a review I profile in the video, “Sufficient scientific evidence exists for public health policy to promote a plant-rich diet for health promotion.”
For those interested in digging deeper, there was an interesting Scientific American blog this summer entitled “Human Ancestors Were Nearly All Vegetarians” and there’s an in-depth video series on YouTube debunking the paleo diet fad. I wrote a whole book on the Atkins incarnation, Carbophobia, now available free online. I also have two videos on low carb diets: Atkins Diet: Trouble Keeping It Up and Plant-Based Atkins Diet.
Michael Greger, M.D.
Image credit: jarapet / Flickr