Mmmmm, yeah, but I think it goes deeper than that.
Common sense tells you that a person is going to eat at restaurants more often when on vacation than when at home.
Chicken in diabetes sauce for every meal abroad = no weight gain
Chicken in diabetes sauce for 75% of meals at home = weight gain
Seems like the industrial food in the US is just shittier than the industrial food everywhere else. It's possible to eat healthy here but you REALLY have to try. You have to have the knowledge, the willpower, time, etc. This is probably why it's the middle class and above who can do it while the poor remain fat.
I've traveled and I've never seen the same things you get chains here be common elsewhere. I just don't eat places that get most of their food from a jar. It's not hard and it's no more expensive, at least where I live, to eat at local owned places that make actual food. If it is, see below
Buy things to make something less terrible. Google for recipes. It's not expensive. Yogurt, some herbs, vinegar and small amounts of butter are probably going to cover most recipes. People have most of those things. Tell me how hard it is to look this up.
The information is easier now more than ever. Same with exercising, YouTube has plenty of videos on starter exercises for people severely out of shape.
The cultural problem is really a problem of Americans not wanting to make a sacrifice.
It's harder for some people financially and culturally but if 40% of people are obese, there's a lot of people who could do something about it. I'll feel bad for the maybe 10% who can't afford better or the ones who are kids.
If you're not willing to switch your snack from chips to a banana, which you know are better and bananas are dirt cheap, as an adult...I don't know what's going to help you but you don't want to help yourself.
It's not the time, it's the giving up the sweet, salty and saturated fat food they love. If they don't want to put in the effort, they'll miss out on benefits like every shit not being an emergency and being able to use the stairs in a fire.
That said, I do think schools should teach healthy life skills as parents clearly aren't.
Edit: my longest post ever I think