Fat replacers are urbanised to duplicate the taste and texture of fat, but contain fewer calories per gramme than fat. Fat replacers usually fall into three categories: carbohydrate-, protein- or fat-based. The ingredients that are worn to replace fat depend on how the food product would be eaten or prepared. For example, not all fat replacer ingredients are heat stable. Thus, the fat replacer that worked well in a salad covering might not work well in a muffin mix.