Calorie, kcal, calorie, calorie and kilojoule are all units of heat, and the conversion between them is:

1 calorie = 1 calorie = 4.186 joules; 1 kilocalorie = 1 macrocalorie = 1,000 calories = 1,000 kcal = 4,186 joules = 4.186 kilojoules. A calorie ("cal", abbreviated "calorie") is defined as the amount of heat required to raise 1 gram of water by 1 degree Celsius at 1 atmosphere of pressure.

1 kilocalorie is equal to 1,000 calories, or about 4,186 joules; fat has about 900 calories per 100 grams; and sugar and protein both have only 400 calories per 100 grams.

Nutrition

With the "15 degrees calories": 1 gram of water at 1 atmospheric pressure from 14.5 ℃ to 15.5 ℃ calories required, the International Committee of the 15 degrees calories is equal to about 4.1855 joules, the National Bureau of Statistics of the 15 degrees of calories is the usual calorie is about equal to about 4.1859 joules. 4.1859 joules.

"4-degree calorie": the amount of heat required to raise 1 gram of water from 3.5 to 4.5 degrees Celsius at 1 atmosphere of pressure.

"20-degree calorie": the amount of heat required to raise 1 gram of water from 19.5°C to 20.5°C at 1 atmosphere, which is equal to about 4.1816 joules.

"Average calorie": the average number of calories per degree required to raise 1 gram of water from 0°C to 100°C at 1 atmosphere, which equals approximately 4.190 joules.

Reference for the above: Baidu Encyclopedia-Calories