That's partly because much of the government subsides go towards subsidizing corn, ending up in high fructose corn syrup and all the junk food most people consume. It's quite sad, that everyone is so okay with this.

Personally, I try to eat as healthy as possible and use my nutrient finder (https://kale.world/c) to find high nutrient, low calorie foods, which end up being mostly beans, vegetables and fruits.