Emily Willingham is a science writer and a co-author of “The Informed Parent: A Science-Based Resource for Your Child’s First Four Years.”
It may be hard to believe, but overeating was once considered a good thing. For early humans, anyway, it was beneficial for stocking up when the next opportunity to get food might be days away. But today, that same instinct has turned into a disadvantage, making us prone to obesity, diabetes and heart disease, Lee Goldman argues in his book “Too Much of a Good Thing.”
Goldman posits that overeating is one of four “key survival traits” — the other three are salt-seeking, anxiety and blood-clotting — that kept humans alive when life was nasty, brutish and short but have over time become threats. These traits have persisted, he says, because we don’t die from them before we’ve reproduced, so the next generations get them, too.
It’s an intriguing idea, and the book promises an engaging read that distills history, evolution and genetics into a neat theory. Unfortunately, Goldman, a cardiologist and dean of the medical school at Columbia University, doesn’t make an entirely convincing case.
He begins by explaining how each of the four traits flipped from good to bad. Salt, for example, was once a scarce commodity, and seeking it out was a lifesaving instinct. Now that it’s all too common in many diets, salt can lead to high blood pressure, stroke and other ills. During Paleolithic times, an amped-up awareness was required to stay alive in a period when dangers lurked around every corner. In modern times, though, that hypervigilance can manifest as anxiety, phobias and depression. Blood clotting, of course, is a vital part of healing. But its extreme efficiency mattered more when deep wounds from combat or predators, as well as bleeding from childbirth, were greater, more wide-scale threats than they are today. Yet our cardiovascular system has not evolved to the changed reality. Clotting inside our vessels can potentially lead to the blockage of blood flow to the heart or brain, and to heart attack or stroke.
Goldman raises some valid points about the negative effects of these traits over the long term. But each of these factors remains important to our survival. We still need salt (just not as much as many of us get). We still need blood clotting (it’s just bad inside our blood vessels). We still need vigilance about ourselves and others (but not so much that we can’t leave the house). And we even still need to eat to satiety, especially when we’re young and growing (but not so much when we’re grown). As Goldman notes, without strong selection to root out these traits, they’re not going away anytime soon. Indeed, it’s unlikely that we’d fare well without them.
Throughout the book, Goldman observes that obesity, anxiety, a salty diet and heart disease are not new. At any point in human history, anyone could have lived long enough to develop some related malady. Even Ötzi the Iceman, discovered after 5,500 years frozen in Alpine ice, had signs of nascent heart disease. Today, though, increased longevity has allowed more people to develop full-blown heart disease, stroke, obesity or depression. Since these “survival traits” have always posed risks for humans who lived long and prosperously enough, perhaps it’s our longer life span that is inherently “too much of a good thing,” rather than these critical traits themselves.
The book’s ultimate conclusion is that medical and pharmacological interventions will help us ward off or treat the negative effects of these good things gone bad. Some readers might see that as a weak finish, but it’s the strongest argument Goldman presents. And caveat lector: Along with being somewhat dry and inconsistent, “Too Much of a Good Thing” suffers from frequent imprecise phrasing of scientific concepts, making it best digested with a grain of salt.
Little, Brown. 352 pp. $28