As someone who believes your right to overeat ends where my airplane seat begins, I don't think that Medicare's decision last week to begin paying for obesity treatments is such a terrible example of nanny-state meddling. The thin already are forced to subsidize the fat anyway, via taxes and higher private insurance costs. Why not pay a little more in prevention now, if that will cut huge Medicare bills for obesity-related problems later? Plus, fat pride activists are appalled by the Medicare decision, which probably means it's a pretty good idea.

Which isn't to say that we shouldn't emphasize personal responsibility when it comes to obesity. Certainly losing weight is difficult; this doesn't mean it's impossible. My friend Greg Critser, author of "Fatland: How Americans Became the Fattest People In the World," argues that beltless pants and limitless refills are symptoms of modern American culture's general lack of boundaries and self-control. He also doesn't like the way upper-middle-class boomer parents, who lead the public discussion, are loathe to talk about limiting children's diets or making them exercise, lest kids end up anorexic or with damaged self-esteem.

"Feminists and liberals have transformed a legitimate medical issue of the poor into identity politics for the affluent," Greg told me, "which I find the worst kind of narcissistic behavior." But he also lacks patience with right-wing complaints about government intervention: "Those libertarians who have all kinds of problems with government programs about obesity are going to be crying their eyes out 20 years from now," he added, when a fat and aging population brings with it increased taxes and social burdens.

Greg is now fit and trim but used to be chubby. At school, he was called Blimpboy and Skipper, after Gilligan's hefty pal. He only took the weight off a few years ago, when a man yelled "Watch it, Fatso!" at him for opening the car door into traffic.

"On the one hand, he's a dick and I'd like to find that guy now," Greg recalled. "On the other hand, the social shaming worked."