The calories in foods depend on their composition and the calorie value of a food is not actually its measured values, but is the average energy of a large number of different samples of the food.

The calories in foods depend on their composition and the calorie value of a food is not actually its measured values, but is the average energy of a large number of different samples of the food. Negative calorie foods are foods, which use more calories to digest than the calories food actually contains! Even though a food may contain equal amount of calories, much less of these calories can possibly turn into fat in negative calorie foods as fewer calories are actually available to the body. A piece of dessert consisting of 400 Calories (actually 400 kilocalories) may only require 150 Calorie (actually 150 kilocalories) to digest by our body, resulting in a net gain of 250 calories which is added to our body fat ! The foods with negative calorie contain sufficient vitamins & minerals that produce enzymes in quantities sufficient to break down not only its own calories, but additional calories from boy in digestion as well.