Why are there so many overweight and obese people in the United States?

The short answer is that many people make poor choices concerning the type of food ingested, the amount of food eaten, and the amount of exercise they get.  Fat, sugar, and salt make food tasty but are high caloric ingredients or powerful appetite stimulants .  We live in a fast food culture because we have busy lives, and few people want to take the time to cook from scratch with healthy ingredients; the convenience of a fast food chain restaurant meal is undeniable.  Many people rush around to more than one job or rush to take their children from one activity to another.  It is a common American way of life to stop at a restaurant that prepares high calorie, high sugar, or high fat foods quickly.  Food manufacturers compete vigorously with each other for this market where palatability and speed of preparation are keys to the success of their product lines.  Until recently there has been little effort on their part to inform the public about the fat, salt, and sugar content of their products and practically no effort to offer more healthy choices.