Tumor is a serious disease that endangers human life and health. According to the study, the incidence rate of malignant tumor in China is 270.59/100,000 and the mortality rate is 163.83/100,000. Among them, lung cancer, stomach cancer, liver cancer, colorectal cancer, female breast cancer and esophageal cancer are common malignant tumors in China, accounting for about 66% of all new cases of tumors; lung cancer, liver cancer, stomach cancer, esophageal cancer and colorectal cancer are the main causes of tumor death, accounting for about 70% of all tumor deaths. Why do more and more people die from cancer when the standard of living has improved and medical treatment has been developed? As early as 1981, British experts Doll and Peto first proposed that 35% of cancer deaths could be attributed to dietary factors. So what kind of diet can help prevent and treat cancer? Response 1: Restrict energy intake Research shows that reducing calorie intake by 40-60% can slow down tumor growth, and restricting calorie intake can enhance the effectiveness of radiation therapy for breast cancer. The mechanisms of calorierestriction (CR) to inhibit tumor growth include: 1) reducing growth factor products and anabolic hormones; 2) reducing oxygen free radical products and regulating endogenous antioxidant system to reduce oxidative stress and DNA damage by oxygen free radicals; 3) reducing plasma concentration of inflammatory factors and enhancing blood corticosteroids, gastric hunger and lipocalin levels, thus reducing tumor growth. 3, reduce the concentration of plasma inflammatory factors and enhance the level of blood corticosteroids, gastric hunger hormone, lipocalin, thus reducing the inflammatory response; 4, enhance the body’s immune surveillance mechanisms related to aging. Countermeasure 2: Reduce glucose intake Glucose transporter 1 (Glut1) is mainly responsible for regulating cellular glucose transport and glucose metabolism. It has been found that its expression is significantly increased in cancer, which provides sufficient glucose and ATP for various life activities such as cancer cell proliferation, invasion and migration, and is closely related to the development of cancer. Since tumor cell metabolism requires the uptake of large amounts of glucose, reducing the glucose concentration in the environment has a selective toxic effect on tumor cells. Studies have shown that under low concentration glucose culture conditions, tumor cells all show rapid apoptosis. And a high-calorie, high-carbohydrate diet may promote cancer cell proliferation and increase the incidence of many tumors. Therefore, it is recommended to consume coarsely processed cereals, legumes, and root vegetables, limit the intake of refined sugars, and replace meals high in refined sugars with meals rich in whole grains and fibers, and dispense with carbohydrate-rich foods when necessary. Dietary fat can alter the function of normal or transformed cells through multiple molecular mechanisms such as regulation of cellular gene expression, cell membrane structure and function, hormone metabolism, lipid peroxidation and free radical formation, immune system response, etc., which eventually lead to abnormal cell differentiation, proliferation and apoptosis, thus affecting the formation and development of tumors. In general, fat accounts for 20% to 35% of total calories, while in tumor conditions fat can account for up to 70% of total calories. Studies have shown that the significantly enhanced antitumor effects of a ketogenic diet can be used as an adjunct to the treatment of malignant gliomas. Triglyceride levels also need to be tested to ensure adequate fat clearance. n-6 polyunsaturated fatty acids promote the production of AA and AA-derived arachidonic acid analogs in cell membranes, which in turn may promote tumor growth and metastasis by promoting inflammatory responses, tumor-endothelial cell adhesion and tumor cell proliferation. On the one hand, n-3 polyunsaturated fatty acids can inhibit these biological effects by antagonizing the evolution of n-6 into AA-derived arachidonic acid-like substances, and on the other hand, they have direct anti-inflammatory effects, thus inhibiting tumorigenesis and development. The addition of ω-3 fish oil fatty milk to PN fluid in postoperative patients with gastrointestinal tumors resulted in significant improvement of immune function, inhibition of inflammatory factor release, decreased incidence of infection complications, and reduced expression of tumor-related factors. Countermeasure 4: Select appropriate proteins and increase supply ESPEN 2009 guidelines: the recommended range of amino acid requirements for oncology patients is at least 1 g/kg/d and between 1.2 and 2 g/kg/d of the target requirement. According to BozzettiF et al: 1. The total protein intake (intravenous + oral) of oncological cachectic patients should reach 1.8-2g/kg/d; BCAA (branched-chain amino acids) should reach ≥0.6g/kg/d; EAA should increase to ≥1.2g/kg/d; 2. During the short-term shock nutrition therapy phase of severely malnourished oncological patients, protein administration should 2. In the phase of long-term nutritional supplementation therapy for mild to moderately malnourished tumor patients, the amount of protein given should reach 1.5g/kg/d (1.25-1.7g/kg/d); 3. When daily diet is insufficient, oral nutritional supplementation should be given, and when oral nutritional supplementation is still insufficient, intravenous supplementation should be given; 4. Glutamine, arginine and branched-chain amino acids can not only improve 5. Supplementation of glutamine can maintain the immune barrier function of the intestine, which can effectively prevent the side effects of chemotherapy drugs on the gastrointestinal tract, nervous system, heart and other organs; 6. Supplementation of arginine can improve the immune function of the body, reduce the synthesis of tumor proteins, and induce apoptosis through NO, thus inhibiting tumor growth; 7. Supplementation of leucine, valine and isoleucine, three branched-chain amino acids, can reduce protein decomposition, promote protein synthesis of the body, correct negative nitrogen balance, and also inhibit the growth of liver cancer cells; 8. Compared with whey protein, whey protein hydrolysate has stronger tumor prevention and inhibition effects. Countermeasure 5: Increase the intake of oxygen Cancer cells are dominated by anaerobic enzymes of sugar. Under aerobic conditions, tumor cells will take in a large amount of glucose, and active glycolysis produces a large amount of lactic acid, resulting in an acidic microenvironment. The acidified extracellular fluid has a catabolic and destructive effect on cellular mechanisms, leading to infiltration and metastasis of tumor cells. As early as 1955, Thomlinson et al. found that hypoxia exists in many malignant tumor tissues, so increasing oxygen intake by moderate amount of oxygen and aerobic exercise can inhibit the growth of tumor cells. To sum up: Among the nutritional countermeasures for tumors, firstly, we need to limit the total energy intake, increase the total calorie ratio of fat to 70%, the target requirement of protein is 1.2-2g/kg/d, and reduce or not consume carbohydrate-rich foods. At the same time, moderate increase in exercise and music therapy may inhibit tumor growth.