Calorie (Cal for short), transliterated from English Calorie, is defined as the heat required to raise 1 gram of water to 1 degree Celsius at 1 atmospheric pressure. The international standard unit of energy is joule.

Generally speaking, there are two kinds of calories: calories, also known as capital letter C, are most commonly used in food labels, which is equivalent to the heat required to raise 1 000 grams of water from 14.5℃ to 15.5℃ at1atmospheric pressure, which is about 4/kloc-. Small card, also known as cal, is common in scientific research literature, 1000 small card = 1 big card.

Heat is a unit of energy and has the function of heat. Just as electrical appliances consume electricity, human daily activities also consume heat.

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.