Nutrition refers to the process that the human body digests, absorbs and utilizes food or nutrients, and it is also the process that the human body obtains food from the outside to meet its own physiological needs, including intake, digestion, absorption and internal utilization.

From low to high, from single-celled organisms to higher animals and plants, from living in water to living on land, the living environment is different and the ecology is different. In this way, the required nutrients and the way of taking nutrients are also different. Nutrients needed by living things are composed of many elements, including hydrogen, oxygen, nitrogen and carbon. These are the main elements that make up the protein of organisms and store energy. In addition, there are a small amount of sulfur, phosphorus, calcium, magnesium, potassium, sodium, chlorine and various trace elements. Some trace elements are only trace elements in organisms.

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According to USDA, a balanced diet consists of four basic foods. They are: dairy products, meat and vegetable proteins, bread and grains, fruits and vegetables. This paper puts forward a new optimized pyramid diet suggestion to help people choose a diet that can supplement essential nutrients and reduce the incidence of many diseases, such as cancer, hypertension, coronary heart disease and stroke.

This suggestion varies according to the calories consumed by everyone (from 1600 to more than 2400 calories). For example, a person who needs 1600 kcal will eat 6 servings of cereal and 3 servings of protein food every day, while a person who needs 2400 kcal will eat 10 servings of cereal and 5 servings of protein food every day. Generally speaking, the intake of fat should be reduced to 30% of the total calories, while the intake of fruits, vegetables and cereals should be increased.

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