Introduction：World Cancer Research Fund has clearly pointed out that poor dietary habits can lead to more than 30 kinds of cancer, and 1/3 of the patients who die of cancer every year are related to poor dietary habits. In our daily diet, we may want to keep in mind five keywords, as far as possible to prevent cancer from the mouth. Eat “fresh” A number of international studies have pointed out that eating more fresh food can help prevent cancer. The World Cancer Research Fund found that eating more fresh fruits and vegetables can reduce the incidence of pharyngeal, laryngeal, esophageal and other cancers. The antioxidants, carotenoids, vitamin C, flavonoids and other active ingredients contained in fresh fruits and vegetables have anti-cancer effects. People should eat at least 400 grams of different kinds of fresh fruits and vegetables daily, preferably including red, green, yellow and purple colors. On the contrary, don’t eat foods that have been left to mold for a long time. Peanuts, soybeans, rice, noodles and other moldy, can produce a strong carcinogen aflatoxin, which can lead to liver cancer, stomach cancer and so on. In addition, try not to eat overnight food, placed more than 8 ~ 10 hours of the dish often contains nitrites, the more times the number of heating the more content. Eat “light” high salt diet and the occurrence of stomach cancer has a close relationship. Japan Cancer Center Research Institute for 40,000 middle-aged people for a period of 11 years of follow-up found that, for men, salt more people suffering from stomach cancer risk is twice as high as those who eat less salt, and in women, salt more people suffering from stomach cancer risk is significantly higher than those who eat less salt. Researchers said that this is because the high osmotic pressure of salt will cause direct damage to the gastric mucosa after the human body consumes too much high-salt food, and then a series of pathological changes will occur. It is recommended that people do not eat more than 5 grams of salt per person per day. Cooking should also pay attention to the existence of “hidden salt”, such as monosodium glutamate (MSG), soy sauce, sauces, seasoning packets also contain salt, need to control the amount. In addition to less salt, light diet should also control the amount of meat. The U.S. National Academy of Sciences reported that fat is most closely related to cancer, especially breast cancer, colorectal cancer and prostate cancer. World Cancer Research Fund suggests that weekly intake of animal and poultry meat should be less than 500 grams, the best not to eat, as little as possible to eat processed meat products. Three eat “coarse” food lack of dietary fiber is one of the important reasons for the increase in cancer patients in recent years. A variety of food is originally a source of dietary fiber, but by the impact of processing, processing the more fine, the more dietary fiber loss. Therefore, it is best for people to deliberately eat some “coarse”. Dietary fiber-rich foods include: black rice, cornmeal, oat flour, fresh corn, millet and other staples; mushrooms, mushrooms, beans, broad beans, garlic shoots, wild rice and other vegetables; pomegranates, mulberries, pears, kiwi, fresh dates and other fruits; black sesame seeds, pine nuts, dry almonds, dry walnuts and other nuts. Dietary fiber into the body, can stimulate gastrointestinal peristalsis, promote defecation, reduce intestinal absorption of carcinogens, prevention of colorectal cancer. It is worth recommending that beans have less fat and more fiber, which can not only effectively reduce the risk of endometrial cancer, but also prevent breast cancer due to the high content of antioxidants. Roughage is also rich in calcium, magnesium, selenium and other trace elements and a variety of vitamins, which can promote metabolism and enhance physical fitness. Among them, selenium is a kind of anticancer substance, can be with the body of various carcinogens “tied together”, through the digestive tract out of the body. It is recommended to increase the intake of coarse grains in the daily diet. For example, oat flour, cornmeal and flour mixed together, made into a variety of bread or noodles; red beans, mung beans mixed together to cook a variety of beans porridge. But note that no matter which kind of coarse grains are steamed and boiled, such as less oil, less salt cooking methods for the best. Four eat “bitter” Many people exclude the food with a little bit of bitterness, but do not know, bitter food has a very good anti-cancer effect. Lemon, citrus, grapefruit, grapefruit and other fruits are a little bitter, because they contain a substance called “citrinin”. Citrinin is a phytochemical usually found in ripe fruits, especially lemon fruits. Studies over the years have found that citrulline is effective in boosting the immune system and may help tumor patients build up their resistance. Research in the United States found that the consumption of citrus or orange juice can be absorbed lemon bitter pigment, oral cancer, lung cancer, breast cancer, stomach cancer and other preventive effects. American research also found that other natural bitter substances in food also have certain health effects. For example, naringenin in lemon and grapefruit, tea polyphenols inside tea, and polyphenols in red wine and chocolate, which are ingredients that help prevent cancer and heart disease. Quinine extract in bitter melon boosts the immune system and helps control blood sugar. Therefore, cancer prevention diet must eat some bitter. Eat “acid” Vinegar is the most common condiment in the kitchen of Chinese people, containing a variety of amino acids and organic acids. Research has confirmed that vinegar contains an enzyme with bactericidal effect, can inhibit the growth of cancer cells, reduce the strong carcinogenicity of aflatoxin. In addition, vinegar can prevent high blood pressure, high blood fat, high blood sugar, reduce fatigue and so on. Many times it is suitable to put vinegar in cooking, which is both healthy and delicious. In addition to vinegar, yogurt is also a common sour food. U.S. research has confirmed that drinking yogurt regularly can inhibit tumors. Researchers first artificially make rats suffer from tumors, and then divided them into two groups. A group of feed with yogurt, the other group does not add. The results show that the former tumor is obviously inhibited, compared with the latter, the tumor cells reduced by 30% to 35%. The reason for this, researchers believe that lactic acid helps inhibit the growth of harmful bacteria such as E. coli, and can phagocytosis of carcinogenic substances, weakening its carcinogenicity. Although yogurt is good, but not too much food, adults do not drink more than 400 grams of yogurt a day, unless it is a great demand for calcium pregnant women, lactating mothers or developing adolescents.