I don't really buy the argument that sugar content is to blame. I buy cheap food, I live in the US, I don't eat "healthy" and never have -- and yet I'm thin. People like to hand-wave this away by telling me I must have a high metabolism, but I've never found that to be a convincing explanation.

I think a more probable reason for the obesity epidemic is the rise of food as a self-soothing device. To me, the best indicator of whether you're likely to have a weight problem isn't your activity level or the sugar content of your groceries, it's whether you turn to food as a way to relax.