I've long suspected that being fat makes you stupid as well - as in the word "fatuous." Have you ever noticed that few obese people are bright? You might be unintelligent to begin with and make poor dietary decisions because with a dull mind you would be inclined to make bad decisions, including those involving nutrition. On the other hand, if you had average or greater intelligence and still are fat, whether through poor genes or just not making the right nutritional or time allocations, you would notice, if ever you were to lose weight, that you start to regain some smarts with weight off. I've been heavy and then shed weight and among the first noticeable improvements were a sharper mind and a desire to better take care of myself, including sacrificing habits and spending more time doing meal prep or exercise - leading to weight loss and increased wellbeing.There is clearly a major problem with the food quality in America. UK too. It's largely not real food at this point. Processed food is the foundation of many peoples diets, which is a terrible mistake they are making. There is more unhealthy food in the US than anywhere else.
What really opened my eyes to it was years ago visiting fast food restaurants overseas, American ones, and walking away realizing the food was of significantly higher quality than back home. Research followed. I soon understood the American restaurant chains serve far healthier food overseas than they do at home. Some due to regulations. Some due to the reality the crap they sell in the states wouldn't sell overseas. Of course that education led to a further understanding that there's many chemicals/pesticides in our food supply which is outright banned in other countries.
All that being said, most Americans are fat because they're lazy. And when I say lazy I mean both mentally and physically. I'm not gonna sit here and sugarcoat it. A lot boils down to convenience. While much of the world still home cooks and prepares the large majority of their meals, many Americans do not. While some may say eating healthy is too expensive, that is false. Eating unhealthier fast food and less filling processed food is more expensive. Americans also move less. Walk less. What it largely boils down to is fewer calories expended and more calories ingested.
And I'm not going to pretend it takes multiple PHD's for people to figure this out. Most people know high activity levels and more exercise equates to more calories burned. And most people know preparing your meals and eating fruits/veggies/meat is much healthier than the alternative.
I recall when I was heavy discussing my weight with my physician. He said "unfortunately, it's on you." As a physician he's obviously sick of giving advice to people regarding their lifestyles which is forgotten by the time of their next meal. A year later, when I next saw him, he lit up and shook my hand with a look of pride (and this is not a friendly guy) because it says a lot to lose weight and keep it off if you once were heavy.
I'm nattering on a bit but I agree with Rainy that you can talk about the scarcity of nutritious food in America and there's truth to it, but, ultimately, start moving more and eating less and eating more nutritiously and you indeed can be less fat.