A fast-food restaurant is a restaurant that serves fast-food. Usually, these restataurants mostly serve food to take away. Many of them do not have a large seating capacity, and often, seating is not very comfortable. The type of restaurant is also known as quick-service restaurant (QSR). The food choice is limited, and usually prepared in bulk in advance. It is either kept hot, or heated up, before it is served. The kind of food is often of a "meat-sweet diet". Very often, fast-food restaurants are part of a restaurant chain or a franchise. The chain or franchise will provide partly-prepared standardized products or ingredients.
Variations on the fast-food restaurant concept include fast-casual restaurants and catering trucks. Fast-casual restaurants have higher sit-in ratios, offering a mix between counter-service typical at fast-food restaurants and a traditional table service restaurant. Catering trucks (also called food trucks) often park just outside worksites and are popular with factory workers.