[junius2020]

It is not just Sugar, it's also the fact that most Americans live on a diet full of industrially refined sugar, hydrogenated vegetable oil, strange chemical preservatives, flavouring agents, artificial sweeteners to avoid the sugar, and "no fat' products that achieve this in strange way. For instance,

It's further complicated by the fact that there is no functional epistemology of nutrition in the US; previous attempts to create one such as the "Food Pyramid" were heavily financed by food lobbying groups and are now distrusted. This leads to things like people deciding that carbohydrates are universally bad because removing deep fried potatos from their diet makes them feel better; or people swearing by vegetarianism because for the first time since childhood they stopped eating "Meat.jpg" like you find in hotdogs etc. Or people swearing by low fat diets because they stopped eating icecream deep fried in margarine.

There is also no underlying national food tradition; I live in South East Asia and in this country there is a strong tradition of eating steamed rice and steamed chicken as a staple food, as well as steamed eggs and seafood (shellfish, pan fried fish,etc) This means that with no nutritional knowledge the diet here is considerably better than the average person in the US.