When I am at the grocery store I play a little game with myself and look at what a person has in their cart then make note of how fit the person looks. It's a pretty good indicator of what works and what doesn't diet wise. You can almost always tell how big a person will be by their cart. Lots of junk food and they are huge. The typical 'diet' foods (lean cuisine, low fat everything) and they are usually pretty large as well. (which says a lot to me about how well the standard 'diet' foods work). Lots of fresh veggies and meats, they are usually pretty lean and fit. All vegan stuff, they are usually skinny-fat or rail thin. I did notice some younger asian woman in their 20s with a cart full of junk food who were pretty thin, but it seems that asians in general can get away with eating a lot of junk, at least when they are younger, and not get fat.
Apathy is tyranny's greatest ally.