Protein is not only the basic building material of life, but also the muscles, bones and internal organs in the body are mainly composed of protein. protein participates in various physiological activities, such as food digestion, oxygen transmission, heart beating and muscle contraction. But also can synthesize hormones that regulate metabolism, such as thyroxine, insulin and various enzymes that catalyze their chemical reactions, as well as antibodies that can enhance the body's defense function. In addition, protein also provides energy for the body and repairs tissues. It can be said that there would be no life without protein. Protein cannot be produced by human tissues themselves, and food is made up of various amino acids, so people must take it from food. There are more than 20 kinds of amino acids needed by human body, among which 8 essential amino acids cannot be synthesized by human body and must be obtained from food, including lysine, leucine, isoleucine, methionine, phenylalanine, threonine, tryptophan and methionine. Other non-essential amino acids are not necessarily obtained from food, but can be synthesized by human body or transformed from other amino acids. In order to meet the needs of synthesizing protein from various amino acids, the human body should eat corresponding different nutritious foods every day.

When the supply of protein in the diet is insufficient, the enzymes that control human metabolism are reduced, the antibodies are reduced, the immunity is weakened, the synthesis speed of collagen cells that make connective tissue is slowed down, and symptoms such as edema, palpitation, fatigue, anemia, lethargy, influence on children's development, mental retardation, menstrual disorder, low resistance, difficult wound healing, muscle atrophy, fracture and the like appear. Protein in food is eaten too much, and protein will produce nitrogen-containing substances such as ammonia, urea and muscle crisp when metabolized in the body. Among them, ammonia is toxic and needs to be detoxified by the liver before being excreted from the kidney. The more protein eats, the heavier the burden on the liver will be, which will do more harm than good, especially for patients with liver and kidney diseases, which will aggravate the condition and cause liver and kidney damage.