By MICHAEL POLLAN
Published: April 22, 2007
A few years ago, an obesity researcher at the University of Washington named Adam Drewnowski ventured into the supermarket to solve a mystery. He wanted to figure out why it is that the most reliable predictor of obesity in America today is a person’s wealth. For most of history, after all, the poor have typically suffered from a shortage of calories, not a surfeit. So how is it that today the people with the least amount of money to spend on food are the ones most likely to be overweight?