[throwaway22032]

You're right, but you're confusing some factors here I think.

The US has higher calorie fast foods, larger default portions, and walking is involved far less in the typical day than in most countries.

That means that if you just do what feels natural, in the US you're going to be eating more and doing less exercise than you would elsewhere.

That's not an argument against willpower, it's in fact the opposite. In the US _more_ willpower is required - you're explicitly going against the norm to an extent, if you move to e.g. Paris and get the metro and walk everywhere then by default you're going to be eating less and exercising more.

I don't think that anyone is claiming that we can reduce the statistical incidence of obesity via willpower. It's more that you, as an individual, can choose to be healthy. It's empowering and therefore important to know that.