>Does that mean Americans are poor people who can only afford empty calories?
I don't know if it's because they can't afford better or don't want to eat better, but in the US there is a considerable relationship between income/education and obesity. The poorer you are, the more likely you are to be obese. 50% of the US makes less than $30k a year, and that group probably amounts to somewhere around 75% of the obese people.