It takes 1 calorie of heat energy to raise the temperature of 1 gram of water by 1 degree Celsius.

The unit of energy is still expressed in terms of "kilocalorie", which is the usual term used in nutrition.1 A "kilocalorie" is the amount of heat required to raise the temperature of 1,000 grams of water from 15 degrees Celsius to 16 degrees Celsius. Its full name is "kilocalorie" abbreviated "kilocalorie" symbol kCal.

Internationally recognized unit of energy is the "joule" (symbol J)1. A "joule" is the amount of energy it takes to move a kilogram of weight 1 meter with a force of 1 "newton". 1000 "joules" is 1 "kilojoule" (symbol kJ). " (symbolized as kJ); 1000 "kilojoules" is 1 "megajoule" (symbolized as MJ).

In nutritional science, energy supply and consumption are generally more than 1 "megajoule", and now there are many in the literature with the "megajoule", here are the conversion of the two units of energy listed below:

1 kcal = 4.184 kilojoules. Joule 1 kilojoule = 0.239 kilocalorie

1000 kilocalorie = 4184 kilojoule = 4.184 megajoule 1000 kilojoule = 239 kilocalorie 1 megajoule = 239 kilocalorie