Main functions of protein powder 1, promoting muscle growth 2, improving immunity 3, repairing cells and building tissues 4, forming all cells and tissues in the body 5, maintaining normal function and metabolism of cells 6, forming enzyme system and maintaining normal digestive function 7. Make blood transport substances and maintain the osmotic pressure of the body. The catalysis of enzymes. Regulating hormone 10, oxygen transport 1 1, muscle contraction 12, immunity 13, scaffold 14, regulating immunity, anti-fatigue 15, and neutralizing body fluids is unnecessary for healthy people. According to the reference intake of dietary nutrients for China residents, it is recommended that the daily intake of protein for adults should be 65 ~ 90g, or 10% ~ 12% of the total energy to meet the metabolic needs. In addition, protein intake varies with people's age, weight and labor intensity. During the growth and development of children and adolescents, pregnant women or lactating women generally have a high demand for protein. For healthy people, as long as they adhere to a normal diet, the lack of protein will not happen. Milk, eggs, meat, soybeans, wheat and corn contain all kinds of essential amino acids in sufficient quantities and appropriate proportions. Therefore, as long as we stick to a variety of foods, we can completely meet the human demand for protein, and there is no need to supplement protein powder. Moreover, the psychological enjoyment and sensory stimulation brought by food can not be replaced by protein powder. You should eat a proper amount of protein powder. For the special population in need, apart from supplementing essential amino acids through food, protein powder can be appropriately selected as the supplement of protein, but we must pay attention to the dosage of protein powder. After protein is digested and absorbed by gastrointestinal tract, it needs to be processed by liver and converted into human substances for human use. At the same time, nitrogen-containing substances such as ammonia, urea and creatinine, which are products of protein's metabolism in the body, need to be excreted through the kidneys. If a person ingests too much protein, it will increase the burden of liver and kidney and have a negative impact on the human body. Therefore, protein is by no means the more the better. The highest intake of protein in the Dietary Guidelines for China Residents is 0.92g per kg of body weight, and if it exceeds this amount, it may be harmful to human health. In fact, protein only needs to meet the needs of human metabolism. After the excess protein is digested and absorbed, the liver will convert them into hepatic glycogen or muscle glycogen for storage; If liver glycogen or muscle glycogen is enough, it will be converted into fat and stored; Other metabolites produced by this transformation must be excreted from the kidneys. Excessive protein not only makes people obese, but also increases the metabolic burden of liver and kidney, which may affect their functions over time. It should be reminded that while supplementing protein, we should also pay attention to supplementing carbohydrates (sugars), lipids, vitamins and minerals. Because the lack of these nutrients will not only affect the utilization and metabolism of protein, but also cause some diseases, which is very harmful to health.