In the study of all the causes, the National Cancer Institute found that about 2/5 of them were related to diet. Their recent research shows that a scientific diet can help you greatly reduce the risk of cancer. Cancer takes a long time to form, which means that you have many years to stop or encourage its formation. Researchers have found that what you eat may interfere with the development of cancer at different stages. For example, some foods can inhibit some carcinogenic chemicals, but others may greatly increase your chances of getting cancer. For example, the pigment added to food is a carcinogenic chemical, and some foods, especially meat, are added with nitrate as a preservative. These nitrates or nitrites can be converted into nitrosamines in human body, which are carcinogens and can cause liver cancer, stomach cancer, bladder cancer and kidney cancer. Some pickled foods, such as salted fish and sausages, contain many of these substances. So eating too much salted fish is one of the reasons for gastric cancer and nasopharyngeal cancer. In addition, rotten food can also cause cancer, such as moldy peanuts and rice, which can breed carcinogenic Aspergillus flavus. Obesity is also one of the pathogenic factors of cancer, which has been confirmed in animal experiments. The researchers experimented with two groups of animals. One group was well fed, and the other group ate it every other day. The probability of cancer in the well-nourished group is about five times higher than that in the other group. According to the report of the American Institute for Cancer Research, there is evidence that overweight and obese people are more likely to develop cancer. The other side of obesity, that is, nutritional deficiency, such as lack of vitamins or some important nutrients, will also increase the risk of cancer. For example, the lack of vitamin B will cause liver diseases and increase the incidence of liver cancer. The lack of zinc, magnesium and other elements is also related to cancer. A high-fat diet and a lot of meat are also important factors of cancer. According to statistics, some western countries with high fat consumption have the highest mortality rate of breast cancer. Another report shows that a high-fat diet, especially in areas with high animal fat consumption, not only has more breast cancer patients, but also has a higher probability of developing colon cancer and front-line cancer. Ethel, a world-renowned cancer expert, said that excessive consumption of meat and other foods rich in cholesterol will not only cause problems such as arteriosclerosis, insufficient blood circulation and cell hypoxia, but also increase the risk of cancer. Animal experiments and clinical experiments also show that limiting the intake of meat and animal fat will reduce the risk of cancer. Americans eat the most meat in the world, and the number of people suffering from cancer in the United States is also the largest in the world. On the contrary, some ethnic groups with low animal protein content in traditional diets have few cancer patients. For example, the Laza people at the southern foot of the Himalayas are low in fat and protein, making them one of the longest-lived people in the world. Meat contains a lot of phenylpurine, which is one of carcinogens. According to research, 1 kg meat contains phenylpurine equivalent to 600 cigarettes. This substance can cause gastric cancer and leukemia in mice, and the content of phenylpurine in barbecue is relatively high. In addition, fatty foods also contain many carcinogens. The content of carcinogenic polycyclic hydrocarbons in high-temperature fried food is very high, which is very dangerous.