America has one of the highest rates of obesity of any nation in the world. Coincidentally, Americans also consume more pre-processed foods, which often contain ingredients banned in many other countries, than many other nations. Given the correlation of obesity and the types of food we consume, it is safe to assume that alternative diets would produce fewer obese people. Given the fact that Americans are already larger than most other people in the world and that the size of the average American is growing larger, it is safe to say that obesity is an epidemic in America.
Epidemic: a widespread occurrence of an infectious disease in a community at a particular time.
Obesity isn't a disease, it's a social thing. It's like "Hey, it's a buffet! I'm going to go eat a bunch of food!"
It's not, "Hey I just shook Newt Gingrich's hand and got the fat disease on me."