American obsesity can correlated to eating too much salt, sugar and fat.<p>Fast food makes it cheap and easy to get into a pattern where a significant portion of your daily intake is essentially a combination of sugar (soda, coffee, tea, etc), fat (burgers, fries, tacos, etc) and salt (flavoring, preservatives, etc.)<p>If we went back to the diet before there was fast-food then we'd have a lot less obesity. People would be eating more whole grains, fruits, veggies, fish and lean meat.