I do agree that fast food restaurants are responsible for the amount of obesity and other health problems in the United States as I have seen many people who most the time have their lunch and dinner at fast food restaurants and are suffering from obesity.
All the food stuff prepared in fast food restaurants is fried and cheese is used in it. This is the main cause of obesity. For instance, burgers and sandwiches, which are liked by most people, have cheese and mayonnaise in them. Fries also cause fatness, and they are mostly served with all food stuff in fast food restaurants. And as we know the United States is a very busy country. Its people don't have time to cook at home. So while working, instead of going home or bringing lunch with them from home, they directly go to fast food restaurants and have their meal over there.