A few weeks ago, I wrote about the political economy of the obesity epidemic. Here, from a great oped in yesterday’s NYT, is the evolutionary science behind both the problem and the solution.
Here’s the argument (though I strongly urge you to read the extremely well-crafted piece):
Since sugar is a basic form of energy in food, a sweet tooth was adaptive in ancient times, when food was limited. However, excessive sugar in the bloodstream is toxic, so our bodies also evolved to rapidly convert digested sugar in the bloodstream into fat. Our hunter-gatherer ancestors needed plenty of fat — more than other primates — to be active during periods of food scarcity and still pay for large, expensive brains and costly reproductive strategies…
Simply put, humans evolved to crave sugar, store it and then use it. For millions of years, our cravings and digestive systems were exquisitely balanced because sugar was rare. Apart from honey, most of the foods our hunter-gatherer ancestors ate were no sweeter than a carrot…it wasn’t until very recently that technology made pure sugar bountiful.*
Here again we run smack into the economics—technology (and trade) has allowed us to push out the supply curve, and thus lower the price, of a food source we crave but that is bad for us in such quantities.
In this regard, as the author puts it, Mayor Bloomberg’s move to ban large sugary drinks, though admittedly “paternalistic,…is not an aberrant form of coercion but a very small step toward restoring a natural part of our environment.”
Libertarians will squawk, and not unreasonably. But as long as the externalities I document in my earlier post persist—and they’re getting worse—the rationale for such policies—bans, Pigouvian taxes, consumer education—is strong and getting stronger.
When science, evolutionary biology, and simple economics all point in the same direction, it’s probably wise to head that way.
We humans did not evolve to eat healthily and go to the gym; until recently, we didn’t have to make such choices. But we did evolve to cooperate to help one another survive and thrive. Circumstances have changed, but we still need one another’s help as much as we ever did. For this reason, we need government on our side, not on the side of those who wish to make money by stoking our cravings and profiting from them. We have evolved to need coercion.
*One question: what about geographies where sugar wasn’t rare, like the tropics (I had some incredibly sweet pineapple this AM)? If this theory is correct, wouldn’t it predict that earlier civilizations in such areas were more prone to obesity? Or is this more about processed sugars?
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