1. Nutrition refers to the function of the human body to absorb necessary substances from the outside to maintain life activities such as growth and development. The modern scientific definition of health is the dynamic balance between body and natural environment and social environment, and it is the perfect state of body, spirit and society. Nutrition is closely related to health. Reasonable nutrition can improve health.

2. In order to maintain life and health, and ensure the needs of physical growth, physical activity and learning and thinking, the human body must constantly absorb necessary nutrients from food. These nutrients include protein, fat, carbohydrates, minerals, vitamins, water and dietary fiber, which are collectively called the seven essential nutrients for human body.

3. Only by reasonably matching and absorbing these nutrients can we maintain normal life activities and good health. However, unreasonable dietary structure, overnutrition or undernutrition are harmful to the body.