What is a calorie and why are diets and dieticians so keen on them? In nutritional terms a calorie is a measurement of energy. Thus a food which contains several calories per ounce can offer you additional energy than one with a coffee calorific price. In strict scientific terms a calorie may be a measurement of heat, and in dietetic terms heat is energy. Calories become vital in dieting as a result of if we have a tendency to don't use all the energy we tend to take in our food, the excess is deposited as fat. The only means we tend to will understand if we are taking in too several calories is by counting up the number of calories we have a tendency to eat per day to lose weight. You would like to take in 350zero fewer calories than your body wants to lose a pound in weight. You lose it because your body burns up its own energy by obtaining its calories from your fat.