Sweet potatoes are low in calories and quite full. Whether it is a staple food or a non-staple food, it is a good diet food. According to the determination, every100g of sweet potato contains only 0.2g of fat. Is this rice? 0? 4。 Therefore, sweet potato is the best among low-calorie and low-fat foods. In addition, sweet potato also contains balanced nutrients. Such as vitamins A, B, C, cellulose and potassium, iron, copper and other trace elements 10, in which cellulose has a good effect of stimulating intestinal peristalsis and promoting smooth excretion. At the same time, because the fiber structure can not be absorbed in the intestine, it has the special function of preventing sugar from becoming fat. Therefore, nutritionists call sweet potato the most balanced healthy food and the most ideal and cheapest diet food. Sweet potato is a kind of cheap and good health food. "Compendium of Materia Medica" records that "sweet potato ... can make people live longer, and has the functions of tonifying deficiency and benefiting qi, strengthening spleen and stomach and strengthening kidney yin". Sweet potato is one of the most balanced foods. 500 grams of sweet potato can produce 630 kilocalories, which contains more protein than rice, white flour and millet, and also contains calcium, phosphorus, iron, carrots and vitamins. Especially valuable are the iron, calcium, carrots and vitamin C that flour lacks, and sweet potatoes are rich in these substances. Vitamin C in sweet potato is comparable to citrus, and vitamin B is 7 times that of rice. Sweet potato has obvious inhibitory effect on malignant tumor. According to 20 kinds of vegetables published by Japan Cancer Institute, sweet potato ranks first. At the same time, it has the function of maintaining the elasticity of blood vessel wall; Prevent visceral connective tissue atrophy; The function of improving the immunity of the body; Anti-constipation effect; Prevention of coronary heart disease; Prolonged aging; The function of prolonging life. Sweet potato is most suitable for porridge, spleen and stomach, and stomach. Benefiting the lungs and intestines in the morning and benefiting the stomach at night. In the morning, it belongs to the lungs and intestines, and at night it belongs to the gallbladder and liver. Like sweet potato porridge and clear porridge. The same people eat, because the time is different, the benefits are different. Knowing the season and time of eating and cooperating with gymnastics movements can make people relaxed and happy. Experts said that sweet potato is rich in starch, carotene, vitamins B 1 and B2, as well as protein, fat, phosphorus, calcium, iron, nicotinic acid and other small amounts of nutrients needed by the human body, which is very suitable for the elderly. American scientists also found that the fiber in sweet potato can absorb a lot of water in the intestine, increase the volume of feces, and relieve constipation as well as drug treatment. Japanese experts have found that polysaccharides such as mucin contained in sweet potatoes can improve immunity, promote cholesterol excretion and prevent arteriosclerosis, which can not be underestimated in reducing the incidence of cardiovascular diseases.