Paleo Diet – Served Up Straight

Banksy’s “Caveman”. Credit: Lord Jim Flickr (CC BY-SA 2.0)

Thanks to Scientific American‘s Guest Blog feature for this interesting fodder for thought.

The “True” Human Diet

From the standpoint of paleoecology, the so-called Paleo diet is a myth

People have been debating the natural human diet for thousands of years, often framed as a question of the morality of eating other animals. The lion has no choice, but we do. Take the ancient Greek philosopher Pythagoras, for example: “Oh, how wrong it is for flesh to be made from flesh!” The argument hasn’t changed much for ethical vegetarians in 2,500 years, but today we also have Sarah Palin, who wrote in Going Rogue: An American Life,“If God had not intended for us to eat animals, how come He made them out of meat?” Have a look at Genesis 9:3.

While humans don’t have the teeth or claws of a mammal evolved to kill and eat other animals, that doesn’t mean we aren’t “supposed” to eat meat, though. Our early Homo ancestors invented weapons and cutting tools in lieu of sharp carnivore-like teeth. There’s no explanation other than meat eating for the fossil animal bones riddled with stone tool cut marks at fossil sites. It also explains our simple guts, which look little like those evolved to process large quantities of fibrous plant foods.

But gluten isn’t unnatural either. Despite the pervasive call to cut carbs, there’s plenty of evidence that cereal grains were staples, at least for some, long before domestication. People at Ohalo II on the shore of the Sea of Galilee ate wheat and barley during the peak of the last ice age, more than 10,000 years before these grains were domesticated. Paleobotanists have even found starch granules trapped in the tartar on 40,000-year-old Neandertal teeth with the distinctive shapes of barley and other grains, and the telltale damage that comes from cooking. There’s nothing new about cereal consumption.

This leads us to the Paleolithic Diet. As a paleoanthropologist I’m often asked for my thoughts about it. I’m not really a fan—I like pizza and French fries and ice cream too much…

…It makes sense, and it’s no surprise that Paleolithic diets remain hugely popular. There are many variants on the general theme, but foods rich in protein and omega-3 fatty acids show up again and again. Grass-fed cow meat and fish are good, and carbohydrates should come from nonstarchy fresh fruits and vegetables. On the other hand, cereal grains, legumes, dairy, potatoes, and highly refined and processed foods are out. The idea is to eat like our Stone Age ancestors—you know, spinach salads with avocado, walnuts, diced turkey, and the like.

I am not a dietician, and cannot speak with authority about the nutritional costs and benefits of Paleolithic diets, but I can comment on their evolutionary underpinnings. From the standpoint of paleoecology, the Paleolithic diet is a myth. Food choice is as much about what’s available to be eaten as it is about what a species evolved to eat. And just as fruits ripen, leaves flush, and flowers bloom predictably at different times of the year, foods available to our ancestors varied over deep time as the world changed around them from warm and wet to cool and dry and back again. Those changes are what drove our evolution.

 Read Peter Ungar’s entire post here.

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