Isocaloric

Part of speech: adjective

Definitions

1. Relating to dietary plans where the caloric intake is identical or equal to the caloric expenditure
2. Characterizing items that possess the same caloric value, making them nutritionally equivalent
3. Pertaining to amounts of energy that remain unchanged or balanced in nutritional consumption

Etymology: "Isocaloric" is built from two parts: the Greek prefix "iso-", meaning "equal" or "the same," and "caloric," which comes from the Latin "calor," meaning "heat." The combination describes things that share the same amount of energy, which makes sense once you know that nutritional energy was originally measured as heat, in calories. The "caloric" half carries the older history. The word "calorie" was adopted into English from French, where it was formed from the Latin "calor," and it first named a unit of heat before it came to describe the energy in food. Attaching "iso-" to it produced a term for two foods, diets, or meals that deliver equal energy, even when their ingredients and nutrients differ widely.