Marc Ambinder (via Ezra Klein) writes in the Atlantic about his own obesity and America's:

Obesity is an almost inevitable consequence of living with our cultural norms, our history of agricultural production and subsidies, our long-standing socioeconomic inequalities, and the impact of technology on our behavior and bodies. Against this formidable dynamic, America has erected two lines of defense: name-calling, and hectoring about diet and exercise.

And that line of defense, Ambinder writes, misses the prime mover in the obesity epidemic. It's not willpower:

The people most vulnerable to obesity, however, do not have access to healthy food, to role models, to solid health-care and community infrastructures, to accurate information, to effective treatments, and even to the time necessary to change their relationship with food. And if that is true for fat adults, it is even more true for fat children, many of whose choices are made for them. Their vulnerability to obesity is much more the result of societal inequalities than of any character flaw.