Nutrition Facts - Energy

Energy is defined as the capacity to do work. Through the process of digestion, we convert the food we eat to energy. This food energy is calculated as Calories (C) or kilocalories (kcal) or Joules (J).

One gram of protein or carbohydrate provides four kcal whereas one gram of fat provides nine kcal.

One kilocalorie is equal to 1000 gram calorie. One kcal is equal to 4186 Joules.

Our body metabolizes carbohydrates, proteins and fats to provide energy. These three nutrients are called proximate principles. Water, vitamins and minerals do not provide any calories.

The amount of energy in a food measured by burning pure samples of food. This is called direct calorimetry. However there are a few losses of energy in the body and hence energy values called the Atwater Bryant factors and thus the following calories have been assigned for different foods.