According to the results of epidemiological surveys, among various factors such as environment, lifestyle, smoking, alcohol consumption, diet, genetic factors, viral infections, psychological state, personality behavior, etc., dietary factors play a very important role in the process of cancer development. For example, some studies have shown that the consumption of salt is positively correlated with the mortality rate of stomach cancer, and the intake of fat and animal protein is positively correlated with the mortality rate of colon cancer, rectal cancer, breast cancer, prostate cancer and pancreatic cancer, etc. We once encountered a case: a girl who loved fried food and had KFC as her staple food developed colon cancer when she was 15 years old. This is a very sad example, so how to carry out proper diet to prevent tumor? 1. Eliminate harmful food intake. Nowadays, there are many carcinogens related to diet: for example, smoke contains more than 40 kinds of carcinogens, aflatoxin in moldy peanuts, nitrosamines in pickled food, benzo(a)pyrene in food smoked with coal and firewood, which are all strong carcinogens. 2, diet should be diverse. Not only protein, fat and sugar, but also vitamins and trace elements, vitamin C and vitamin E can reduce the production of peroxides and free radicals in the body and reduce the mutation of chromosomes; stomach vitamin A and carotene can increase the stability of mucous membrane; many trace elements are involved in the composition of enzymes and can improve the phagocytosis of reticulocytes and leukocytes to improve the body’s resistance to disease; selenium can increase the stability of mucous membrane. Selenium and germanium can reduce free radicals, and their intake is negatively correlated with tumorigenesis. Such as carrot, cabbage, lettuce, cabbage, fern, jujube, cinnamon meat, lotus seed meat, grain skin, wheat skin, etc. contain various essential nutrients, vitamins and trace elements. 3, pay attention to the ratio of fat and protein intake. The metabolites of fat and protein — amine-containing substances have the risk of inducing intestinal cancer if they stay in the intestine for too long. The United States proposed in the 2000 cancer prevention plan to reduce the fat content of the diet to 25% to effectively prevent intestinal tumors. 4.Increase the intake of fiber. Fiber can increase intestinal peristalsis, reduce the residence time of amine-containing substances in the body and improve constipation, and fiber contains more polysaccharides, which are beneficial to health, such as mushroom polysaccharide and silver fungus polysaccharide with immune enhancement and anti-cancer effects. Some experts predict that: due to the improvement of food structure, at least the incidence of cancer in the United States may be reduced by 30% to 60% [6]. 5.Create good eating habits. Slow food, diet, light food, fresh food, fixed food [7], avoid hot food, too hot porridge, noodles accelerate the increase of esophageal epithelial squamous cell necrosis, easy to induce esophageal cancer.