I find this article from Megan McArdle at The Atlantic to be extremely interesting:
This week, Health Affairs published a new study showing that–quelle surprise!–obesity accounts for an ever growing share of our health care costs. They put the number at about 10%. So I decided to ask Paul Campos, the author of The Obesity Myth, what he thought. The book, which everyone should read, argues that the health benefits of losing weight are largely imaginary; that we are using “health” to advance our class bias in favor of thin people, particularly thin women. […]
Megan: Let’s start with the first. If there’s one thing that everyone in America knows, it’s that being fat is really unhealthy. Why do you call it a fake problem?
Paul: The correlations between higher weight and greater health risk are weak except at statistical extremes. The extent to which those correlations are causal is poorly established. There is literally not a shred of evidence that turning fat people into thin people improves their health. And the reason there’s no evidence is that there’s no way to do it.
So saying “let’s improve health by turning fat people into thin people” is every bit as irrational as saying “let’s improve health by turning men into women or old people into young people“. Actually it’s a lot crazier, because there actually are significant health differences between men and women and the old and the young — much more so than between the fat and the thin.
Megan: So why is the public health community so set on this issue as the major driver of our health care costs?
Paul: Because we’re in the midst of a moral panic over fat, which has transformed the heavier than average into folk devils, to whom all sorts of social ills are ascribed.
Megan: Aside from rising health care costs?
Paul: Well according to the obesity mafia our kids are all going to die sooner than their parents, which sounds like a moral problem as well as one of health care costs. It’s all complete nonsense.
Megan: Do you think being overweight is a proxy for things that DO make a difference, like fitness?
Paul: It’s a weak proxy, but yes it has some marginal significance. It’s good to encourage people of all sizes to be active and avoiding eating disordered behavior (like dieting), but this isn’t because lifestyle changes will make fat people thin people. They won’t. I’d like to talk a little about the statistics if I may.