About Units

Calories: Calories (cal) are a unit of energy. Specifically, they are defined as the amount of heat needed to raise the temperature of one gram of water by one degree Celsius. In nutrition, calories measure the energy content of food, with 1 food calorie (kcal) being equal to 1,000 small calories.

Megajoules: Megajoules (MJ) are equal to 1,000,000 joules. This unit is commonly used to describe large quantities of energy, such as the energy content of fuels, electrical energy, and the energy output of engines.