Fast food is designed for convenience, long shelf life, and flavor. It's usually calorie-dense and easy to overconsume, but there's more to it than that. Not only are many of these foods unhealthy, but they also provide little nutritional value, hence the term "junk food."
These foods are usually high in fat, sugar, sodium, and many ingredients that have been linked to a range of health problems when consumed excessively. But what are the worst foods in American diets? Click through the gallery to find out.