MARLENE ZUK IS AN EVOLUTIONARY BIOLOGIST at the University of Minnesota. Her last book was a pithily entertaining look at sex on six legs. In her new book, she has jumped from bugs to humans. Paleofantasy: What Evolution Really Tells Us About Sex, Diet, and How We Live contains a tiny bit about two-legged sex, quite a bit more about human diet, but mostly it dissects our fantasies about the distant Paleo-past. In particular, it addresses the currently popular notion that if we adopt the lifestyle of our Paleolithic ancestors — whether that means running barefoot, or heaving boulders in one of the nation’s “CrossFit” studios, or eating raw meat still dripping with blood — then we’ll be more in sync with our real natures. As she points out, a growing number of Manhattan urbanites and Silicon Valley types are zealously, indeed quasi-religiously, trying to access their inner “Grok” (lingo, in case you didn’t know, for their Paleo- or cave-selves). But, they’re barking up the wrong tree, and missing the real lessons of evolution, according to Zuk.

¤

Michele Pridmore-Brown: You just wrote Sex on Six Legs, which makes sense in terms of your work on crickets and sexual selection, but now, in this book, you’re busting a cultural myth about our hominid evolutionary past. How are they related?

Marlene Zuk: The two books are more connected than people might think. A lot of my day job — as a biology professor and researcher — got me interested in rapid evolution and how quickly change can happen. Our work on crickets showed that a mutation that alters their wings and makes males unable to chirp spread throughout the population in fewer than 20 generations, remarkably quickly in evolutionary terms. Being unable to chirp protected them from a parasitic fly, so that’s why the mutation was advantageous. I started thinking more about what determines the rate of evolution. Lots of new evidence is suggesting that some traits in people, such as adaptation to high altitude, might also have evolved very quickly. This then made me ultrasensitive to all these mentions in the press and popular literature and even in conversation about how we humans have gotten out of sync with our environments because we evolved as hunter-gatherers in the Paleolithic — some x thousand years ago, say 10,000 to 200,000 years ago. The idea is that, because of modern life, we have developed this awful malaise: we’re out of sync with our real selves and the best way to remedy that is to mimic the diet, exercise, and childrearing practices of way back when.

MPB: In your book, you’re very specific about the form these attempts at mimicry take — for instance, supposed Paleo diets that eschew starch and allow only roots, berries and meat; so-called “CrossFit” exercises that mimic running from lions and heaving boulders, and so on. It seems like you’ve got two things going on: consumers misunderstanding evolution, and then Paleo-fantasies as a kind of secular religion.

MZ: When I was researching this book, I read a lot of stuff on Paleo blogs and websites, and I can tell you I was struck by how deeply invested people are in a particular version of what the past is like. And now I should mention my caveat that I am not writing a diet book. I don’t care what people eat; or rather, I&r...