Pleistocene Diets

It seems as if every six months there's a new crop of diet books peddling a new weight-loss gimmick. The latest are the so-called Pleistocene diets that exhort us to eat as a caveman (or woman) did in order to live a long and healthy life. The idea is that humans didn't evolve on French fries and ice cream. Instead, survival during our formative years was fueled by eating more meat, which allowed our early ancestors' brains to get bigger than those of other primates. So forget the pasta, and load up on roast beef, these books urge. Your body will thank you later.

As always, the devil is in the details. Obviously, much of what our early ancestors ate must have been good for them. But there's a lot of variation even among today's ever dwindling population of hunter-gatherers. The further back in time we look, the less precise our knowledge of diets becomes. There's controversy among paleoanthropologists about whether meat or the advent of cooking contributed more to our evolutionary success. Two weeks ago, researchers from South Africa and France presented evidence that a major source of protein for early hominids was termites , a food group none of the new diets recommend.

So I had to laugh when one Pleistocene diet book declared that we shouldn't eat beans because they have to be cooked before they can be digested. Humans may have been using fire for some 1.6 million years! Other books ban carrots and potatoes because they're "too domesticated"--as if early humans never ate roots or tubers.

I was just about ready to give up on all the paleonutritional advice books when I came across an advance copy of Elizabeth Somer's The Origin Diet (Holt; $23), due in bookstores this month. A registered dietitian, Somer has done an admirable job of taking what's known about paleonutrition and adapting it to fit our modern lifestyles. Unlike many ancient-diet gurus, for example, she says it doesn't make sense for us to eat more than 20% of our calories in the form of protein since few of us will ever be as fit as our ancient forebears were. She also permits nonfat dairy products because there simply aren't as many sources of calcium in diets now as there were 40,000 years ago.

There's even a role in the Origin Diet for grains, which paleopurists consider off limits because agriculture didn't develop until 10,000 years ago. The key, Somer says, is to stick with whole grains, using them to replace the wild grasses that were staples of many ancient diets.

The food plan Somer proposes turns out to be pretty close to the one modern nutritionists are most familiar with--a diet low in saturated fat and high in complex carbohydrates. There's an ultrahealthy emphasis on fruits and vegetables (eight to 10 servings a day), legumes and lean meat (especially fish and skinless chicken breast)--as well as lots of regular exercise. What's missing is the highly refined products and fried foods we've come to associate with modern American cuisine.

It will take a lot of planning to stick with the Origin Diet. My guess is that some of the more rabid ancient-diet advocates wouldn't consider it a true paleolithic prescription. But I think Somer has the right idea. Just be glad you don't have to hunt down a woolly mammoth for dinner.

For more about paleonutrition, visit our website at time.com/personal . You can send e-mail to Christine at gorman@time.com