Carbohydrates can provide heat for the human body. Carbohydrates in food are divided into two categories: effective carbohydrates that can be absorbed and utilized by people and ineffective carbohydrates that cannot be digested by people. [4] Carbohydrate is the main source of energy for all living organisms to maintain life activities. It is not only a nutrient, but also has special physiological activities.

Carbohydrates are composed of three elements, carbon, hydrogen and oxygen. There are many organic compounds with broad-spectrum chemical structure and biological functions in nature. It can be expressed by the general formula Cx (H2O) y. Because the ratio of hydrogen to oxygen in it is two to one, which is the same as water, it is called carbohydrate.