Calorie

Calorie, amount of heat required to raise the temperature of one gram of water one centigrade degree (more precisely, from 14.5C to 15.5C). One kilocalorie is the amount of heat required to raise 1 kg of water through 1 centigrade degree and is therefore equal to 1,000 calories. The calorific value of foods is actually a measure of the number of kilocalories that can be obtained by the body, in the form of energy, when the foods are broken down.

See also: British thermal unit.