Calories are units of energy. Mainly used to calculate the nutritional energy of food, the international standard unit is Joule. Generally speaking, adults need at least 65,438+0,500 calories a day to maintain body functions, including body temperature, cardiopulmonary function, brain operation and other basic metabolism. Basal metabolic consumption varies with individual height, weight, age and gender. The application of specific calories needs to be combined with individual basic metabolism, food composition, energy needed for life and so on to formulate personal nutrition recipes.