Economic theory explains why kids are getting fat :: CBS News

People respond to incentives. Facts fit the theory.

Quote:

On average, children in the study gained 29 pounds. But for the region with the highest relative price for produce - Mobile, Ala. - children gained about 50 percent more excess weight as measured by body-mass index (a ratio of height to weight) than children nationally.
. . .
Advocacy groups have suggested a strong link between obesity and the proximity of fast-food restaurants or the lack of supermarkets stocked with fresh food. But the new study by the Santa Monica-based Rand Corp. think tank found little support for that connection.

Here's the Rand press release.

It's also true that in the U.S. the poor are getting richer. And that that increase in income isn't going into vegetables so much as chips and sodas. (Students, what does that tell you about the income elasticity of vegetables?) Quote:

Elizabeth Frazao, a U.S. Department of Agriculture economist, noted that a separate USDA study showed low-income consumers, when given an additional dollar, didn't increase their purchase of fruits and vegetables.