> If not than in our society almost everybody would be obese.

Isn't that already the case. I'm of belief, the failing isn't individual but societal. You have obese toddlers and wild animals in the US.

I don't think this is a failure of willpower, it's a failure to investigate the actual causes of the obesity epidemic. Maybe it's sugar, perhaps it's highly processed oils, etc. Whatever it is, people aren't investigating it thoroughly enough.