It doesn't help that the whole environment in America works against you - huge portions (much, much more than you need), artificial sweeteners and everything else put into processed to make it more appealing. Then you have obese people and their kids saying things as: "Vegetables are not tasty", because their baseline is super sweet, flavored food, which is also the worst food possible for your health.
One also need to understand this is business - healthcare is private. More obese people = more patients = more money. Healthcare industry is not making money when everyone is walking around without cigarettes, alcohol, eating health, exercising.