Sweet potato contains protein, starch, amino acids, pectin, dietary fiber and other vitamins and minerals, as well as more than ten kinds of trace elements such as calcium, iron, copper, selenium and potassium. Sweet potato contains a lysine substance, but rice and flour just lack this lysine. Eating sweet potatoes with rice noodles can fully supplement protein. Sweet potato contains a lot of dietary fiber, which cannot be digested and absorbed in the intestine. Can stimulate the intestine, enhance peristalsis and promote defecation. Sweet potato is famous for its low calorie and high fiber. It contains almost no fat and cholesterol and is rich in unsaturated fatty acids, which is unmatched by other foods. Dietary fiber can not only prevent the absorption of fat and cholesterol in the intestine, but also decompose cholesterol in the body, promote lipid metabolism, effectively prevent overnutrition and resist obesity, thus achieving the purpose of losing weight. Dietary fiber in sweet potato also has the special function of preventing sugar from being converted into fat. In addition, sweet potato contains a lot of starch, which can produce satiety after eating, thus reducing food intake and reducing weight. Sweet potato contains a substance similar to estrogen, which has a certain effect on protecting human skin and delaying aging. Eating sweet potatoes can inhibit the production of melanin and prevent freckles and senile plaques. Sweet potato is also rich in potassium, which can alleviate the disadvantages caused by excessive salt intake. Potassium and sodium are important elements that affect blood pressure, and taking enough potassium can eliminate excess sodium. Sweet potato is rich in vitamin C, carotene and folic acid. Eating sweet potatoes often helps to maintain normal folic acid levels in the human body. Eating sweet potato in daily diet can quickly neutralize the acidic substances produced by rice, flour, meat, eggs and other foods in human body, maintain the weak alkali balance of human blood, and at the same time convert carotene into vitamin A.