The Paleo Diet, Debunked

Elise Solé

Unless you've been living in a prehistoric cave, odds are that you've read about the Paleo diet, the weight-loss program de jour. Its concept is simple: Eating a diet of fruit, vegetables, red meat, and fish, foods that caveman supposedly consumed during the Paleolithic era 10,000 years ago, will help cure ailments such as obesity, acne, low libido, and autoimmune disease. The diet has spawned dozens of books, magazine articles, and reportedly celebrity fans such as Kim Kardashian, Jessica Biel, Megan Fox, and Miley Cyrus.

But Marlene Zuk, Ph.D., Professor of Biology at University of California-Riverside and author of Paleofantasy: What Evolution Really Tells Us About Sex, Diet, and How We Live tells Slate that the roots of this diet are less evolutionary and more nostalgic. "You see this attitude in what can be referred to as "paleo-nostalgia"—the notion that we were all better off before agriculture, or civilization, or the Industrial Revolution," she says. "It's not to say life has been unmitigatedly getting better. But it's more helpful and accurate to see that all organisms are constantly evolving. There has been no point in our past when we were perfectly adapted to our environment. I'm not dismissing the idea that you need to look at our evolutionary heritage to think about what's best for us health-wise. But when you start plucking out pieces in an oddly specific way, you can run into trouble."

What's more, says Zuk, we don't really know what cave people were eating. "It's turning out that they may have eaten more starch and carbohydrates than we had realized. They also ate different things in different parts of the world. So it's hard to come up with this one perfect human diet that everybody was eating. Plus our genes have changed in the last 10,000 years. Lactase persistence—the ability to digest milk as adults—is the poster child for this. Our genes have changed extremely rapidly so that at least some populations of humans can digest milk into adulthood. And just as with lactose, it turns out that in human populations that consume a lot of starch, there are more copies of genes that allow starch breakdown. All of this suggests that evolution is happening all the time and much more quickly than people think." Added to the fact that food has changed so much over the years that almost every item in your run-of-the-mill supermarket, even Whole Foods, is genetically different then its prehistoric counterpart. To say the diet emulates what cavemen ate, may be a bit of a stretch.

And while it's true that our ancestors likely adopted a diet of 100 percent unprocessed food and were constantly exercising (being chased by a saber-toothed tiger can do that to a person) unlike the average computer-bound professional (walking to the salad place on your lunch break doesn't count), Zuk says that ancient remains show about the same incidences of modern-day cancer. Plus, cavemen, who typically lived until only about 18-years-old didn't consume grains, dairy, salt, and sugar—at worst, that's no bagels, fro-yo, and fries; at best, no quinoa, Greek yogurt, or almonds. Fun factor aside, carbohydrates are essential for energy and brain function, salt for nerve function, and dairy for strong bones. That doesn't sound like a well-balanced diet. 

A happy medium? Feel free to adopt the healthy basics of the Paleo diet (no junk food) but live a little!