Fat, Drunk, and Broke? Don’t Blame the Caveman

Spare a thought for the most abused demographic in the US today: the Pleistocene hunter-gatherer. These plucky ancestors, who scurried across the earth from two million to 12,000 years ago, have lately taken responsibility and blame for seemingly every aspect of modern life.

Cavemen-bashers would have us believe that because our brains evolved in a world where hunting and gathering were requisite skills, not juggling frequent flier points or angling for a promotion, we’re ill equipped to deal with modern life. We want to be good, but our brains are forever subconsciously pulling us back to our cavemen ways. Marital fidelity? Not in our genes. Peaceful co-existence? Not adaptive for life on the savannah.

Lately, Pleistocene hunter gatherers seem to be getting an especially harsh ragging on behalf of the obesity epidemic. If the last time you stepped on your bathroom scale it broke, the common wisdom seems to be, just blame the atlatl-wielders.

In the May/June issue of Psychology Today, Leyla Muedin argues in “The Way We Were” (p. 51) that “our bodies are best adapted to what our Paleolithic ancestors ate.” Back in the good old days, she writes, “over the course of a year, you might eat 100 different types of fruit and vegetables… but you wouldn’t drink any milk or consume any dairy products.” She quotes S. Boyd Easton, an anthropologist at Emory University,who wrote in a recent editorial in the American Journal of Clinical Nutrition that “the dietary and lifestyle difference between then and now account for most of our chronic diseases and cancer.”

How is this absurd? Let me count the ways.

  1. Hunter gatherers do not, as a rule, enjoy robust health. They must endure the vagaries of the natural world without recourse to the food stores we slovenly civilized folk take for granted. Rather than eating a varied diet, indigenous people have to make do with whatever handful of foodstuffs happens to be available, if any. The uncomfortable reality of hunter gatherers is that they frequently starve to death. The average life expectancy of a Paleolithic hunter was less than 30 years.
  2. Our ancestors did not evolve for any particular environment, for any particular diet. Premodern humans lived in a huge variety of settings, from the arctic tundra to tropical jungle, from remote Pacific islands to high-altitude deserts. There is no such thing as a “hunter-gatherer diet.” Think you need to eat a lot of nuts and wild grasses? Tell it to an Inuit.
  3. We didn’t evolve during the Pleistocene. By which I mean, we didn’t evolve just during the Pleistocene. Our 23,000 genes are the legacy of 3.7 billion years of evolution; the Pleistocene era accounts for less than 0.1 percent of that. Much of our metabolism dates back to the days when were amoebas. (We are insanely hardy buggers!) And what’s more, we continue to evolve. A gene that allows us Europeans to digest milk sprang up about 7,500 years ago in the wake of the domestication of cattle. I’m of European descent; why shouldn’t I consumer dairy? I evolved for it!
  4. Nobody’s a perfect fit. Yes, we live in a different world from our ancestors. But so does every organism. Nature is a dynamic and unpredictable place, and every organism has to constantly adjust. Our environment is different because we have changed it, but we are not unique in that regard. A general evolutionary principle is that behavior precedes adaptation. An organism begins to exploit a new resource, and then changes to exploit that resource better. Thus, a duck is only going to start growing webbing between its does after it starts mucking around in the water. Perfection is a moving target.
  5. For a bunch of misfits, we’re doing pretty well. Yes, we’re a nation of tubbies. But our life expectancy is high and continues to climb. A person born today can expect to live to 78 – two and a half times longer than a cave man. So where’s the dysfunction, exactly?
  6. Cavemen have enough problems. Angry mammoths, giant cave bears, angry spirits – the last thing they need is a bunch of whiny descendents giving them posthumous grief. So let’s declare a moratorium. No more ragging on Pleistocene hunter-gatherers.