Yeah, if anything it is known for sugar in everything that's not supposed to be sweet and corn syrup where you'd expect normal sweetness from sugar. And absurdly large portions.
Personally I have only tried some of the more "famous" sweets such as twinkies and reecies or whatever it's called, and I found both disgusting. The former are just weirdly greasy cake dough filled with teeth hurtingly sweet goop, so intense you can't taste anything else. And the other made me gag after just a small bite and was entirely too sticky for my taste.
I also tried imported "original" Mac and cheese and that stuff was just repulsive too. Weirdly bland and the consistency of snot.
Well, that's what your pop culture tells us Americans like to eat.
So the thought process is something like "I really dont care for instant foods available here, but the Americans reference it all the time sometimes even as a kitchen staple. So maybe they have that shit figured out" and then you try it and get results such as mine.
It also doesn't help that I can't go to an actual American restaurant, you know, being a continent away and all. Best I can do is maccas or Burger king, not even the chains you got over there that are supposedly good. If you're lucky there is a pizza hut in a major city
What era or genre are you getting the pop culture from? Twinkies at least have only been a joke in media for at least 15 years because of zombie survival stuff, and longer as a 'haha look at the fat kid' before that. Die Hard uses them as a comedic element to break up parts of the film but in less of a joking about Twinkies directly way, though it is part of the overweight cop's character. That movie is nearly 40 years old though and probably marks around the time Twinkies started shifting from a snack to a meme
Edit to add: They also originally had banana flavored filling. You can still find these sometimes and while not good they're better than the plain ones imo
Pop culture also says french people eat snails all day and british people use no spices and only one of those is true ;)
But, yeah, don't take the international brands as an example of what Americans typically eat. I mean, some people do, but most people don't eat out most of the time anyways
The real issue is that in American food they are much more willing to throw out the idea that food should be healthy and nutritious for profit and quantity.
It's more that the restaurant industry is so big and specialized over here that if you want to eat healthy there are establishments for that, and if you want OP's experience there are others for that. If you want the freshest, healthiest menus with scratch-made dishes you patronize local businesses. If you want the name brand dishes—most which are precooked and reheated—you go to one of the nationwide chains.
True, but if you can have both, why not? You don't have to eat a whole combo yourself, my SO and I usually share an order of fries, don't get sodas, and get our own burgers. If we go to a sit down restaurant, we'll usually share an entre and maybe order an extra side if we don't think it's enough.