Calories

What is a calorie?
The term calorie refers to the unit of energy: there are regular calories and kilocalories. For most practical purposes, when we say calorie, we mean kilo-calorie in the United States in the content of food.

Small calories
The gram calorie or small (symbol: cal) is the approximate energy required to heat the temperature of one gram of water by one degree Celsius.

Kilocalorie
The large calorie, kilogram calorie, dietary calorie, nutritionist's calorie, nutritional calorie or food calorie (symbol: Cal, equiv: kcal) is equal to the energy needed to raise the warmth or temparature of one kilogram of water by one degree Celsius.

The term kilo means 1000 and therefore, the large calorie or Kilocalorie is equal to 1000 little calories or one kilocalorie (symbol: kcal or Cal).

Joules and calories
The metric system uses joules and one little calorie is roughly 4.2 joules. The large calorie is broadly utilized as a unit of food energy in the US, UK and some other Western countries.

Average calorie needs
An average person needs approximately 2000 calories to not to lose or gain weight.

Age and gender Estimated calories for those who are not physically active

Also see Empty calories