I think you're associating a poor diet with ideas of fast food. Obesity isn't exclusive to the US. I think the issue has more to do with how sedentary we've become vs. the "toxic" food we eat. I would argue that our food safety standards are relatively high compared to others.
Discussion
It’s common nomenclature to refer to this style of eating as the “standard American diet”.
I think we just use shit ingredients and Europeans don’t allow that crap in their countries. When I go to europe, it doesn’t seem like they eat healthier, but I don’t feel like shit after eating out.