Calories, abbreviated as cards, are transliterated from English. It is defined as the heat required to raise 1 kg of water to 1 degree Celsius at 1 atmospheric pressure. Calorie is a kind of calorie unit, which is widely used in nutrition measurement and fitness manual. The international standard unit of energy is joule. As the legal unit of food calories, joules are widely used in Europe, while calories are used in the United States. Although Joule is the legal unit in China, calories are still widely used in Chinese mainland and Taiwan Province provinces due to tradition.

Calories, most commonly used in food labels, are equivalent to the heat required to raise 1 000 grams of water from 14.5 degrees to 15.5 degrees at1atmospheric pressure, which is about equal to the internal energy of 4 186 joules. Cam, which is equivalent to the heat required to raise 1 g water from 14.5 degrees to 15.5 degrees at1atmospheric pressure, is often found in scientific research literature.

Physiological function of heat:

Just as computers consume electricity and trucks consume oil, so do human daily activities. Heat not only provides energy for people's exercise, daily work and life, but also provides energy for human life activities, blood circulation, breathing, digestion and absorption. People who lose weight can burn fat through exercise, which can accelerate calorie consumption and achieve the goal of healthy weight loss.

Even if you lie still, your body still needs energy to maintain body temperature, cardiopulmonary function and brain operation. Basal metabolic consumption varies with individual height, weight, age and gender. Human survival needs energy, which is obtained from food. The calorie content in food is a measure of how much potential energy food produces.