Definition of Fast foods:

Fast foods are quick, reasonably priced, and readily available alternatives to home cooking. While convenient and inexpensive for a busy lifestyle, fast foods are typically high in calories, fat, saturated fat, sugar, and salt.

Fast food chains and restaurants have responded to the public's increasing awareness about nutrition and have attempted to help people concerned about health. For example, they now make ingredient and nutrition information available on their menus. Despite these changes, however, in order to maintain a healthy diet, it is necessary to choose fast foods carefully.

Function:

Most people today have less time to select, prepare and eat food than their grandparents did. Fast foods are very appealing because they are widely available and inexpensive.