Sweet potato is rich in starch, dietary fiber, carotene, vitamins A, B, C and E, as well as potassium, iron, copper, selenium, calcium and other trace elements 10 and linoleic acid. With high nutritional value, it is called the most balanced healthy food by nutritionists. These substances can maintain the elasticity of blood vessels and are very effective in preventing and treating habitual constipation in the elderly. Unfortunately, most people think that eating sweet potatoes will make people fat and dare not eat them. In fact, on the contrary, eating sweet potatoes will not only make you fat, but also help you lose weight, keep fit, prevent sub-health, and relieve constipation and detoxify. Every100g of fresh sweet potato contains only 0.2g of fat, which generates 99 kilocalories of heat energy, which is about 1/3 of that of rice. It is a good food with low fat and low heat energy, and it can effectively prevent sugar from transforming into fat, which is conducive to weight loss and bodybuilding. Sweet potato contains a lot of dietary fiber, which cannot be digested and absorbed in the intestine. It can stimulate intestinal tract, enhance peristalsis, relieve constipation and detoxify, especially for senile constipation. Pay attention to steaming and cooking sweet potatoes. Eating sweet potato should not be excessive, and it should be used with caution for those diagnosed as dampness blocking the spleen and stomach and qi stagnation in traditional Chinese medicine. Sweet potato, a health food in the motorcycle industry, has become a health food in the motorcycle industry in recent years. Europeans and Americans regard it as the "second bread", scientists in the former Soviet Union say it is the future "space food", and the French call it a well-deserved "advanced health food". Sweet potato, also known as sweet potato, sweet potato, sweet potato, yam and so on. It is an annual plant of Convolvulaceae. Because of different regions, people call it sweet potato, Sichuan sweet potato, Beijing sweet potato and Fujian sweet potato. Its hometown is South America, and it was introduced to China at the end of 16. Nowadays, there are traces all over China except the Qinghai-Tibet Plateau. There are many varieties of sweet potatoes, and their shapes are spindle-shaped, cylindrical, oval and spherical. Skin color is white, light yellow, red, yellow and purple; The flesh color is yellow, apricot yellow and purplish red. Sweet potato is rich in nutrition, and it is a natural nourishing food for both food and vegetables. Modern scientific research has confirmed that sweet potato contains many nutrients needed by human body. Every 500 grams of sweet potato can generate about 2658.75 kilojoules (635 kilocalories) of heat energy, including protein 1 1.5 grams, sugar 14.5 grams, fat 1 gram, phosphorus 100 mg and calcium 90 mg. Among them, the contents of vitamin B 1 and vitamin B2 are 6 times and 3 times higher than those of rice, respectively, and the contents of vitamin C are 6 to 30 times higher than those of apples, grapes and pears. In particular, sweet potatoes are rich in lysine, which can promote human metabolism and development, while rice and flour just lack lysine. In addition, the mixed eating of sweet potato and rice flour can give full play to the nourishing function of protein and improve its nutritional value. Sweet potato also contains a lot of mucus substances, including mucin and mucopolysaccharide. They can keep the elasticity of human cardiovascular wall, prevent the occurrence of atherosclerosis and keep the lubrication of respiratory tract, digestive tract and joint cavity. In addition, the starch and cellulose contained in sweet potato can absorb a lot of water in the intestine and increase the volume of feces. This can not only prevent constipation, but also reduce the occurrence of intestinal cancer. Sweet potato contains a lot of cellulose and pectin that are not easily destroyed by digestive enzymes, which can stimulate the secretion of digestive juice and gastrointestinal peristalsis, thus playing a laxative role. Li Shizhen's Compendium of Materia Medica records that sweet potato has the efficacy of "tonifying deficiency and benefiting qi, invigorating stomach and kidney yin". "Sweet potatoes are steamed, cut into sections, dried, and harvested as food, which is called potato food, which makes people live longer and less sick." There is also a medical book saying that sweet potato is "the same as yam, which benefits people for a long time and is a food for longevity". People often add sugar to sweet potato and japonica rice porridge to make porridge, which is used to treat night blindness, bloody stool, constipation, damp heat, jaundice, blood deficiency, irregular menstruation and other diseases caused by vitamin A deficiency. In recent years, the Japanese have set off a series of "sweet potato fever", and men, women and children like to eat all kinds of sweet potato foods (such as baked sweet potato, sweet potato sauce, sweet potato wine, etc.). The reason is that Japanese scientists have found that sweet potatoes have many special "medicinal values". More interestingly, an American biologist found that sweet potato contains "dehydroandrostenol", which has a certain anti-cancer effect. Several researchers from the Crop Research Institute of Beijing Academy of Agriculture and Forestry Sciences and the Animal Center of China Military Medical Science extracted the tumor suppressor of sweet potato for the first time in China, and successfully completed animal experiments. Experts believe that sweet potato is a good anti-cancer product. Sweet potato is longevity food again. In the rural longevity area of Japan, residents eat sweet potatoes from 10 to April of the following year. There are two longevity towns in Guangxi, and residents often take sweet potatoes as their staple food. At present, Japan, the United States and other countries have a craze for eating sweet potatoes, and they also regard it as a good complementary food for babies. Some people say that eating sweet potatoes will make people fat. This statement has no scientific basis. In fact, sweet potato not only won't make people fat, but also is an ideal diet food. Its calories are very low, much lower than ordinary rice. You don't have to worry about getting fat after eating it, but you can lose weight. So many foreign women regard sweet potato as beauty food. Located in the kingdom of Tonga in the South Pacific, most residents are muscular and well-proportioned, which is closely related to their daily eating of sweet potatoes. Sweet potato is crisp and sweet when eaten raw, which can replace fruit; Cooked food is sweet, eaten in the mouth and sweet in the heart. It can be used as both staple food and vegetable. There are many methods of steaming, boiling, frying, frying and frying. Once cooked skillfully, it can also become delicious on the table, such as "red mud" and "Huang Liang" in Sichuan, which are sweet, crisp and delicious; Shaanxi's "vinegar-fried shredded sweet potato" is sour, spicy, crisp and tender, and has a unique flavor. In addition, "Li Xiang potato chips" in Fujian and "osmanthus sweet potato cakes" in Hubei are famous local flavors. Sweet potato with seasoning rock sugar and honey can be made into "sweet potato with honey juice" with orange-red color and soft and tough entrance, which is more characteristic of sweet potato flavor. Sweet potato is steamed, mashed, ground into mud, and mixed with flour to make various cakes, buns, jiaozi, noodles, etc. Dry powder into powder, you can add eggs to make cakes, puddings and other snacks. Sweet potato wine, preserved fruit, vermicelli, etc. It is also full of flavor.