CALORIE

(Abbreviation cal) (1) Basically, A unit of heat energy equal to the amount of heat needed to raise the temperature of one gram of water one degree Celsius (C). More precisely, any of several approximately equal units of heat, each measured as the quantity of heat required to raise the temperature of 1 gram of water by 1C from a standard initial temperature, especially from 3.98C (corresponding to the maximum density of water), 14.5C, or 19.5C, at 1 atmosphere pressure. Also referred to as the Gram Calorie and the Small Calorie. (2) The unit of heat equal to 1/100 the quantity of heat required to raise the temperature of 1 gram of water from 0C (its freezing point) to 100C (its boiling point) at 1 atmosphere pressure. Also referred to as the Mean Calorie. (3) The unit of heat equal to the amount of heat required to raise the temperature of 1 kilogram of water by 1C at 1 atmosphere pressure. Also referred to as the Kilocalorie, Kilogram Calorie, and Large Calorie. (4) A unit of energy-producing potential equal to this amount of heat that is contained in food and released upon oxidation by the body. Also referred to as the Nutritionist's Calorie. The calorie is used when temperature is measured in degrees Celsius (C) on the Centigrade Scale. The British Thermal Unit (BTU) is used when the measurement is in degrees Fahrenheit (F) on the Fahrenheit Scale.