Porridge has a history of nearly 3000 years in China. Li Shizhen, a great physician in Ming Dynasty, said in Compendium of Materia Medica that porridge is "extremely soft and greasy, compatible with the stomach and intestines, and a recipe for diet". Lu You, a famous poet in the Song Dynasty, even thought that eating porridge could prolong life. It is recognized by the medical profession that porridge can tonify yin, promote the growth of gastric juice, strengthen the spleen and stomach, and tonify deficiency, which is most suitable for nourishing people. Protein, fat, vitamins, minerals, starch and other nutrients needed by human physiology mainly come from various foods that people eat daily. These foods are decomposed into small molecules with simple structure, which can be absorbed by the human body. Therefore, the softer the food, the easier it is to be digested and absorbed by the human body, that is, the higher the nutritional value of the food. As far as porridge is concerned, because porridge is boiled at a relatively low temperature for a long time, it is beneficial to reduce the decomposition and destruction of protein and fat, reduce the loss of some vitamins, and make some minerals escape and dissolve in the soup, which can make porridge more nutritious. Moreover, the biggest feature of porridge is that besides the main raw material is grain, it is supplemented with various ingredients with medicinal value, such as lotus seeds, coix seed, lily, lentils, red dates, poria cocos, yam, walnuts and so on. Or mutton, beef, fish and bone marrow rich in protein, or dark vegetables and fruits rich in vitamins. After being boiled by different processing methods, it is not only nutritious, but also delicious. It also has the effects of nourishing, eliminating diseases and building body. For example, lotus seed glutinous rice porridge can nourish the liver and improve eyesight; Codonopsis pilosula meat and bone porridge can greatly replenish vitality; Sesame porridge can moisten the intestines and relieve constipation; Lotus leaf porridge can reduce fat and lose weight. Therefore, according to the nutritional characteristics or ingredients contained in various foods, they can complement each other and make porridge more nutritious. In addition, for children with low level of digestion and absorption, the elderly, the weak and the disabled, eating porridge is more meaningful for nutrition and health promotion. When people reach old age, the functions of various organs of the body gradually decline, especially the functions of taste, chewing, digestion and absorption, and they are prone to various chronic diseases. Therefore, according to the physiological and psychological characteristics of the elderly, eating porridge for the elderly is more conducive to nutrition and health.