Elizabeth Kolbert, writing in the New Yorker, asks a simple question: Why are we so fat? The short answer -- We eat too damn much -- is unbefitting a proper New Yorker essay, and so we're served a long, fascinating look at the literature of "weight-gain" books that aim to explain how Americans gained more than a billion pounds in the last ten years. The most convincing answer I found is: Price and elasticity of appetite.
Kolbert, reviewing The Fattening of America by Eric Finkelstein and Laurie Zuckerman, notes that food has gotten cheaper relative to the other goods and services. And fatty foods have gotten a lot cheaper. The price of soft drinks, for example, have dropped by more than 20 percent, and they now account for seven percent all calories in the US. The New York Times offered a striking graph that told just that story:
But, Kolbert follows up with a good question: Sure, food became cheaper -- fatty food especially. But that doesn't mean our bellies had to grow at an equal and opposite pace. Why didn't we just spend less money easting less? How did our appetites grow so suddenly in the 1980s and 90s?
The most convincing idea she floats is the "elasticity of the human appetite." Simply stated: We have no idea how hungry we are, so we respond to growing portion sizes with growing appetites. In one depressing experiment, participants ate bowls of
pasta soup that were secretly being refilled through a hidden tube. On average, people eating out of these "trick bowls" consumed 73 percent more than the regular bowl eaters. Somewhere between our brain and our stomach, the word "stop" is swallowed -- along with a lot of calories.