We instinctively seek out foods high in fat or sugar - the nutrients best suited to keeping us alive through the famine just around the corner. And we conserve our physical energy, so that we'll be well-rested when our very survival requires exertion. People are prone to gluttony and sloth because, in a world of brutal toil and scarce food, it made sense to take advantage of the rare opportunities to gorge and loaf. In modern America, though, these opportunities are perpetual. Most people can easily afford to buy and eat as much as they want.
Most people can also avoid any physical activity.
A.D. Public health scolds demand that the government require better nutritional labeling and provide more education about obesity in public schools. There are even proposals to slap taxes on fatty and sugary foods - as we do on liquor and cigarettes. And it's just a matter of time before some crusading attorney files a lawsuit against McDonald's for damaging his client's health with its lethal products. But obesity is no more an excuse for the government or the courts to meddle in this aspect of our lives than AIDS is a reason to outlaw non-marital sex. If people want to get fat and die young, that's their decision - and if we don't want to pay their medical bills, we don't have to.