Fast food refers to a type of food that can be prepared and served quickly. It is typically inexpensive, convenient, and ready-to-eat meals or snacks that are sold in restaurants or takeout outlets. Fast food is often associated with popular chains such as McDonald's, Burger King, KFC, etc., which offer a wide variety of burgers, fries, sandwiches, and other fast food items. The term "fast food" also encompasses drive-through windows, delivery services, and packaged or processed foods that can be heated up at home in minutes. Fast food is typically high in calories, fat, sugar, and sodium, making it an unhealthy option for those watching their diet.