As for all Americans being fat, that is just another stereotype like all British have rotten teeth or all Polish are stupid.
Americans probably have worse teeth. Our dental coverage sucks. $700 for a root canal. Most people just have them removed which is a cheap $200.
Anyway, about fat people. They are all over. What ever happened to the civilizations where plumper women were the beautifuls ones? If a natural disaster happened I would hope I had some extra weight! It's the skinny ninnies that are going to go first.
You also have to think about all the crap they put in foods these days. Nothing is natural anymore. Even the young girls are developing at a much faster rate than before, if you get what I mean. My mom says it's in the chicken :)
America - too much Tv watching. Available foods...Not to mention you CANT walk anywhere. The layout of my city atleast it would take a day to get somewhere and even then you have do dodge highways, cars, buses, no sidewalks.....it is a number of things..