In addition to Diet other words or phrases are used to identify and describe these foods including Light or Lite, Low Calorie, Low Fat, No Fat, Fat Free, No Sugar, Sugar free, and Zero Calorie. In some areas use of these terms may be regulated by law. For example in the U.S. a product labelled low fat must not contain more than 3 grams of fat per serving; and to be labelled fat free it must contain less than 0.5 grams of fat per serving.

The process of making a diet version of a food usually requires finding an acceptable low calorie substitute for some high calorie ingredient. This can be as simple as replacing some or all of the food's sugar with a sugar substitute as is common with diet soft drinks such as coke.

Diet food (or dietetic food) refers to any food or drink whose recipe has been altered in some way to make it part of a body modification diet. Although he usual intention is weight loss, sometimes the intention is to aid in gaining weight or muscle as in bodybuilding supplements.

Recipe comes from the Latin word recipe 'take (imperative)', that is, an instruction to have the ingredients ready, originally used in doctors' orders to pharmacists.

Some recipes will note how long the dish will keep and its suitability for freezing. Earlier recipes often included much less information, serving more as a reminder of ingredients and proportions for someone who already knew how to prepare the dish. Recipe writers sometimes also list variations of a traditional dish.

A calorie is a unit of measurement for energy. In most fields, it has been replaced by the joule, the SI unit of energy. However, the kilocalorie or calorie remains in common use for the amount of food energy.

In some scientific contexts such as physics and chemistry, the name "calorie" refers strictly to the gram calorie, and this unit has the symbol cal, a symbol also used by many for the large calorie. Prefixes are used with this name and symbol, so that the kilogram calorie is often known as the "kilocalorie" and has the symbol kcal.