America is not so much a big country, but more like a big business. There is a lot of money to be made in obesity for a lot of people and companies: healthcare, pharma, sugar, hfcs, fastfood, supermarkets etc.

It's in America's interest to keep people fat, keep prisons full, keep hospitals full, charge people for as much as they can, and fleece them out of their money. Of course everyone has to keep up the pretense that the opposite is true, and many may even believe it. But ask yourself this: do you trust their words or their actions?