Studies have shown that 1/3 of all cancers are diet/nutrition related and about 30-40% of cancers worldwide can be prevented by dietary changes. Tumors arise from a particular clone of cells and usually require more than 20 years of accumulation of phenotypic changes to form a tumor. Diet may influence the development of tumors at all times of a person’s life, including childhood. For example, China and Japan have the highest incidence of stomach and liver cancer in the world. When their nationals immigrate to the United States, the incidence of these two tumors decreases dramatically, while the incidence of colon and breast cancer increases dramatically, showing the same spectrum of tumor incidence as that of U.S. citizens, for which the Americanization of dietary habits is the most important reason. In view of this, in October 2007, the World Cancer Research Fund and other global authoritative organizations released the 2nd edition of “Oncology Diet and Guidelines” in several cities around the world at the same time. The guidelines suggest that in terms of dietary choices in daily life, one should be selective and moderate, as briefly described below. 1. Control calories As the saying goes, “Eat one or two bites less at each meal and live easily to 99”. Epidemiological survey found that limiting calorie intake can make people live longer and can prevent tumors. Restricting calorie intake can affect the body in terms of reducing oxidative damage, increasing apoptosis and affecting metabolic enzyme functions, such as lower blood sugar and lower insulin levels. It also enhances self-phagocytosis and certain DNA repair processes. Therefore, for the sake of their health, we must “control the mouth”. 2. Control fat Reducing fat intake is the first choice of anti-cancer diet. It is best to control dietary fat intake to less than 30% of total calories. Beef, lamb and pork are called red meat, while fish and poultry are called white meat. Epidemiological studies have found that people who eat red meat have an increased risk of colon cancer and breast cancer, while eating white meat can prevent dyslipidemia and cardiovascular diseases in adults, therefore, it is recommended to consume an average of 50~100 grams of white meat per day and eat white meat 2~4 times per week. Meat products made by curing, smoking, drying, baking or adding chemical preservatives are called processed meat products, including ham, bacon, sausages, hot dogs, etc. A recent study by the World Cancer Research Fund found that consuming processed meat products can also greatly increase people’s risk of developing colon cancer. 3. Increase fruits and vegetables Vegetables and fruits have been shown to have a preventive effect on many types of cancer. The American Cancer Society recently issued a statement that consuming five servings of fruits and vegetables daily can reduce the risk of cancer because fruits and vegetables are rich in various vitamins, minerals, and antioxidants. More than 25,000 different phytochemicals with cancer-inhibiting properties have been identified in fruits and vegetables. These phytochemicals are safe to use and most of them act on a variety of cell signaling pathways, among which the main carcinogenic substances are: carotenoids, vitamins, resveratrol, quercetin, silymarin, sulphoraphane and indole-3- carbinol. carbinol). Cooking process of fruits and vegetables to destroy the beneficial components, the ideal way to eat is to wash and eat raw. 4, increase grains Whole grain foods mainly include wheat, rice and corn, others also include barley, sorghum, millet, rye and oats. They are rich in vitamin E, triene-tocopherols (tocotrienols), phenolic acid, lignans (lignans) and inositol hexakisphosphate (phytic acid) and other substances that have anti-cancer effects. Meanwhile, whole grains are richer in antioxidant substances than fruits and vegetables. During the refining process of cereal coarse grains, the carbohydrate concentration increases and some beneficial trace elements, such as vitamins and minerals, are lost, resulting in a decrease in the beneficial effects of refined grains. For example, through the refining process, the content of vitamin E in refined grains is reduced by 92% compared to coarse grains. Studies have shown that eating more cereal grains can reduce the risk of oral cancer, throat cancer, esophageal cancer, gallbladder cancer, bowel cancer, breast cancer, liver cancer, endometrial cancer, ovarian cancer, prostate cancer, bladder cancer, kidney cancer, thyroid cancer, lymphoma, and leukemia. Different studies have shown that consumption of whole grain foods can reduce the risk of different cancers by 30-70 percent.