What Is a Kilocalorie (kcal)?
Definition
Kilocalorie (kcal): The energy unit used for food energy and daily energy needs. One kilocalorie is 1,000 calories, or 4.184 kilojoules; the “calorie” of food labels and everyday speech is a kilocalorie.
A kilocalorie (kcal) is the unit for the energy in food and the energy the body needs in a day. One kcal is 1,000 calories, or 4.184 kilojoules (kJ). The SI unit of energy is the joule. The “calorie” of everyday speech and food labels is really a kilocalorie. The calorie calculator gives its results in kcal per day.
Where it appears in the formulas
daily energy need (kcal) = BMR (kcal) × activity factor. A moderately active woman with a BMR of 1,384 kcal needs 1,384 × 1.55 = 2,145 kcal a day. To convert to kilojoules, use kJ = kcal × 4.184.
Calorie or kilocalorie?
In science a calorie (cal) is one thousandth of a kilocalorie. It is too small for food, so food energy uses the kilocalorie and simply calls it a “calorie”. Food labels give energy in both kJ and kcal; according to FAO, 1 kJ is 0.239 kcal.