Have you spent time in rural or poor areas or the US? Try eating the local food. It's not good. As an american who moved abroad, I can say american food is just shockingly low quality. High fat and/or high sugar, lots of highly processed food. Very common attitude that "I have never and will never like vegetables". I mean I'd expect some people live off a diet like sugary cereal, soda, milk, wonder bread, mac and cheese, mayo, ground beef, eggs, candy, fries, pizza, etc. Keep in mind the most common vegetable that americans eat is the potato.

That being said, it is absolutely not the individuals fault for being obese. I'm convinced there are effects that are hormonal, chemical polutants, or epigenetics that push the population to being fatter. The lack of education, and knowledge of how people live in other parts of the world does not help either.

Its a problem for sure. A large portion of the obese tend to be poor people who are working 40-80hours a week with half and hour to 2 hours commute every day who possibly have kids to take care of and may or may not be a single parent household, fast food isn't the cheapest option, but its the cheapest option they have time or the energy for. Also, since most fat food (and most other processed or prepared food sources) know how addictive high calorie and high salt foods can be they will happily take advantage of under educated and over stressed people by cramming as much as they can afford into their food. That of course doesn't apply to everyone and plenty of people who have no excuse are still fat but that applies to a rather large chunk of the overweight people. That also exposes a whole bunch of other issues that need to be addressed as well.

Sad, yes. But surprising? It's been going on for literally hundreds of years…