In recent years, the incidence rate of colorectal cancer in China has increased significantly. With the improvement of economic level, the diet of Chinese residents has become more and more refined, and the poor dietary habits of long-term consumption of high-calorie, high-fat, high-protein and low-fiber foods are closely related to the occurrence of colorectal cancer. At the same time, Chinese people generally have weak knowledge about diet and do not pay much attention to the close relationship between diet and cancer. Research shows that diet containing a large amount of saturated fatty acids can increase the concentration of bile acids in the colorectum and change the composition of intestinal flora, and bile acids can generate carcinogenic substances through the action of bacteria. Food fiber, including cellulose, pectin and lignin, can absorb water, increase the volume of stool, shorten the time for stool to pass through the colorectum and reduce the time for carcinogens to come into contact with the intestinal mucosa. Inadequate intake of dietary fiber is also one of the factors in the development of colon cancer. Therefore, scientific dietary structure and reasonable dietary habits can prevent the occurrence of colorectal cancer to a great extent. How to develop scientific dietary habits from the perspective of cancer prevention? First of all, a balanced diet is an important way to avoid the lack of various nutrients. Partial eating habits are undesirable, especially in the modern fast-paced society, one should not just pursue convenience and simplify the diet, but consciously intake various nutritional elements. Calcium and vitamin D have potential anti-cancer effects Calcium and vitamin D metabolism are closely related, and a study further found that the incidence of colorectal cancer among people who consume sufficient amount of vitamin D in their daily diet is only half of those who consume a small amount of vitamin D; while the incidence of colorectal cancer among people who consume about 1200 mg of calcium or more per day is only equivalent to one-fourth of those who consume less than 625 mg of calcium per day. Therefore, scientists have concluded that calcium intake is negatively associated with the risk of colorectal cancer, while vitamin D has a potential anti-cancer effect. Experts recommend that a daily calcium intake of 1800 mg for men and 1500 mg for women is an appropriate dose for effective colon cancer prevention. In addition all adults should have an intake of 200 international units of vitamin D (5 micrograms/day). Reduce fat intake and promote a low-fat diet Epidemiological studies have found that diets in areas with a high incidence of colorectal cancer are characterized by high fat, while diets in areas with a low incidence are lower in fat. In-depth studies have found that a high-fat diet can cause an increase in bile acid metabolites (deoxycholic acid and lithocholic acid), cholesterol metabolites (steroids and solid ketones), and bacterial glucuronidase activity in the stool, all of which are either carcinogens or carcinogenic and may lead to colorectal cancer. Therefore, excessive fat diet is directly or indirectly related to colorectal cancer. Encourage the consumption of fiber-rich foods such as fresh vegetables and fruits Those who do not like vegetables, fruits and coarse grains should pay attention to adjust their habits. It is found that the lack of fiber in food can reduce the amount of stool and slow down the intestinal peristalsis, so the concentration of carcinogenic substances in the intestine increases and the time of carcinogenic substances acting with the mucous membrane of the intestinal wall is prolonged, and colorectal cancer can easily occur. More konjac, soybean and its products, fresh fruits, algae, etc.; more vegetables rich in dietary fiber, such as celery, leek, cabbage, radish and other green leafy vegetables, dietary fiber-rich vegetables can stimulate intestinal peristalsis, increase the number of bowel movements, and take away carcinogenic and toxic substances from the stool. Dietary fiber should be supplemented with more than 35 grams of dietary fiber daily. Carotene, vitamin B2, vitamin C and vitamin E have a role in reducing the occurrence of colorectal cancer. If there is a long-term lack of these vitamins in the diet, it may promote the possibility of colorectal cancer. Eat more fruits to replenish carotene and vitamin C; consume walnuts, peanuts, dairy products and seafood in appropriate amount to replenish vitamin E; you can eat foods with anti-tumor effect and enhance immunity, and pay attention to the intake of foods rich in trace elements of selenium such as malt, fish and mushrooms. The increased chance of colorectal cancer in those who often eat pickled foods may be related to the carcinogenic substances produced in the process of food pickling. They should try to eat less pickled foods. Regular consumption of onion and garlic foods can reduce the incidence of colorectal cancer, and the mechanism of cancer inhibition may be related to reducing the damage of carcinogenic substances to the mucous membrane of intestinal wall. In summary, the occurrence of colorectal cancer is very closely related to poor dietary habits. Although the occurrence of colorectal cancer is not entirely determined by dietary habits, after all, poor dietary habits can greatly promote people’s chances of developing these cancers. Health education for Chinese people, especially dietary health education, is very important. Scientific dietary structure and habits should largely prevent the occurrence of colorectal cancer.