Lack of calcium intake may also trigger the occurrence of colorectal cancer, mainly because calcium can combine bile acids and fatty acids, which may reduce the contact time between the wall of the colon and some of these bile acids to prevent the occurrence of colorectal cancer. Excessive intake of high animal fat foods may increase the concentration of bile acids in the stool, which may contribute to the development of colorectal cancer, and in the stool test of patients with colorectal cancer who like to eat high-fat foods, it was found that the bile acid content is many times higher than that of low-fat diets and normal people, and the cholesterol content is more than double that of healthy people. In addition, high-fat foods are often high in calories. According to the relevant recent studies, calorie intake is too high, weight may be overweight, may also increase the chances to colorectal cancer. 3, often eat pickled foods, there is a higher amount of nitrate and nitrite, can be synthesized with secondary amines in meat amine nitrite, is the direct culprit of gastrointestinal tract cancer. In smoked foods contain up to 107 micrograms of strongly carcinogenic 3,4-benzopyrene; electric oven smoked meat, 23 micrograms per kilogram of meat; in smoked meat and fried foods also contain more heterocyclic amine compounds. The World Health Organization stipulates that acrylamide should not exceed 1 mg per kilogram of food, acrylamide can lead to genetic mutations and induce benign or malignant tumors. 4, intake of vitamins A, C, E and the mineral selenium reduced, may reduce the body’s antioxidants, affecting the growth and differentiation of colonic mucosal cells, leading to colorectal cancer. 5.Lack of fiber intake can also lead to colorectal cancer, most of the fiber from vegetables and fruits, it is combined with carcinogenic substances, can adsorb bile acid, cholesterol and harmful substances, plus it is insoluble and has water retention, can increase the amount of stool, can also promote the peristalsis of the colon, so that the adsorbed carcinogens quickly discharge, reduce the occurrence of colorectal cancer, on the contrary, too little fiber intake, there is a possibility of cancer. Many people have the illusion that colorectal cancer is a matter of middle-aged and elderly people, and young people are not included in the list. This is mainly because: colorectal cancer is often asymptomatic in the early stage, and when non-specific symptoms such as blood in stool, abdominal pain and diarrhea appear, it is already in the middle and late stage. According to a survey of more than 29,009 male cancer patients in Los Angeles, the more physical activities they engage in, the lower the incidence of colorectal cancer, while the incidence of colorectal cancer among those engaged in low activity is 1.6 times higher than that of those engaged in high-speed activity. It was found that colon cancer is the most obvious among colorectal cancers related to physical activity. Therefore, those who are sedentary in the office are reminded that to maintain health they must adhere to physical activity and exercise so as to reduce or avoid the occurrence of colorectal cancer. How to actively and effectively prevent the occurrence of colorectal cancer? Eat more fruits and vegetables to prevent colon cancer. Fruits and vegetables are rich in fiber, and fiber may have the following effects on tumor prevention: reduce the contact between colon and cancerous substances by speeding up the transport time of colonic feces; increase the volume of feces, which can dilute or affect the concentration of carcinogenic substances in the intestine. Studies have shown that the risk of colon cancer is three times higher when bowel movements are 100 g per day than when bowel movements are 200 g per day. It is believed that the amount of bowel movement is related to the loss of DNA injury of intestinal mucosa caused by fecal fluid in the lumen; it facilitates intestinal flora to change the metabolism of carcinogenic bile acids to reduce the formation of secondary bile acids. In addition to eating more fruits and vegetables and reasonable diet, we should also pay attention to the following issues: develop a good habit of regular bowel movements to keep normal and smooth stools. Participate in sports and increase the amount of activity. Maintain a good psychological state, not to be too happy or too sad when things happen. Actively prevent and treat precancerous lesions of colorectal cancer, such as colorectal polyps and ulcerative colitis, etc. High-risk groups should be examined regularly.