Fast food is the name given to food that is prepared in shops and which can be ordered over the counter as whole meals. That is what makes it different to snacks.

The most famous fast foods are hamburgers. These are a meal made up of a piece of warm, cooked meat (the burger) with salad, all enclosed in a bun. So you have protein (to help grow new tissues) and fat (for energy) in the burger, vitamins and minerals in the salad, and carbohydrate (for energy) and roughage (for good digestion) in the bun. It is, in fact, a balanced meal.

Many people complain about fast foods like hamburgers being unhealthy, but this is mainly because of the sauces (often called relish) put on them. So, for example, tomato ketchup has high levels of sugar and salt, as does mayonnaise. Without the sauces they are quite healthy. Many companies are now trying to cut back on the amount of salt and sugar in their sauces, but this is quite hard because it is salt and sugar that makes things taste good (and not just in fast foods).