But Pollan's nutritional Darwinism only makes sense if the selection pressures of the distant past were in perfect alignment with the health concerns of today. In other words, our food culture would have evolved to protect us from cancer, heart disease, and obesity only if those maladies had been a primary threat to reproduction in the ancient world. It's hard to imagine that the risks posed by these so-called "diseases of affluence"—which often strike late in life, after we've had babies—would have been as significant to our fast-living, sickly forebears as the dangers of, say, bacterial infections or the occasional drought. Indeed, for much of human history, natural selection might well have traded off the dangers of morbid obesity to mitigate the risk of starvation. There's just no way to know how the ancient culinary traditions will fare in the modern world until we try them.
Modern nutrition may be more of an ideology than a science, but so is Pollan's nutritional Darwinism. The two ideologies stand in direct opposition to one another, with the science-minded progressives on one side and the culinary conservatives on the other. The Darwinists reject the idea that lab science can be used to engineer public health on a massive scale. They rely instead on the time-tested mores that have always been our guides. Pollan's reflections on the diet revolution could be an homage to Edmund Burke: Our radical eating habits have produced a swinish multitude.
A conservative approach to eating seems very straightforward, which gives it an enormous appeal. We'd be healthier, Pollan argues, if we just stopped thinking and worrying so much about food and let nature take its course. (He takes several opportunities to congratulate the svelte, chain-smoking French for their pleasure-based cuisine.) But there's no reason to believe that nutritional Darwinism will give us any more clarity on its own terms.
Health gurus routinely use the same language of ancient culinary traditions to sell fad diets that would make Pollan cringe. Barry Sears, author of the low-carb Zone diet, suggests a return to the traditional food culture of the "Neo-Paleolithic" period, when caveman "decathletes" consumed large amounts of meat and very little grain. In his version, we bungled up the natural selection of foodstuffs when we invented agriculture. Pollan says that happened during the Industrial Revolution. Two evolutionary stories offer very different nutritional advice. How can we know who's right?
If we had only the rhetoric of natural selection to go by, we'd never know for sure. Lucky for us, humans have gradually developed the means—over centuries of cultural evolution, no less—to evaluate one claim against another on the basis of objective facts. For all its foibles, food science has given us a reliable set of data on what works and what doesn't. As Ben Goldacre points out in the New Statesman, solid epidemiological work has validated the standard advice we get from our doctors: Exercise more and eat your fruits and vegetables.
Pollan cites the same scientific research to support what he describes as his "flagrantly unscientific" diet plan: "Eat food. Not too much. Mostly plants." I'm happy to follow those dicta if they'll help me to live a longer, happier life. But that doesn't mean I have to buy into the misleading, great-great-grandma-knew-best philosophy that spawned them. I'd rather stick to the science, warts and all.