There are four kinds of bad lifestyles that are closely related to cancer as follows. 1. Unreasonable diet: It includes long-term excessive cream and thick flavors (super-abundance of nutrient-rich foods, including high-calorie, high-protein and high-fat foods), excessive alcohol consumption, insufficient intake of fruits and vegetables, and long-term consumption of pickled or fried foods. The development of stomach cancer, intestinal cancer, laryngeal cancer, esophageal cancer, pancreatic cancer, bile duct (cyst) cancer, lung cancer, breast cancer and prostate cancer are all related to improper diet. Smoking: lung cancer, liver cancer, stomach cancer, esophageal cancer, colorectal cancer are closely related to long-term smoking or passive smoking. 3. Psychological tension and pressure: too fast pace of life, long-term psychological tension, excessive work and life pressure and poor venting, irregular living and disorganized life rhythm can trigger the occurrence of stomach cancer, breast cancer and prostate cancer. 4. Lack of exercise and overweight: Often take the car instead of walking, take the elevator instead of walking, modernize the office, socialize the housework and even walk less and less in modern times, the incidence of overweight and obesity is getting higher and higher. And almost all common cancers (except lung cancer) are related to obesity. Therefore, a few years ago, the WHO put forward through reasonable living habits to prevent cancer 5 recommendations are: 1, avoid animal fat; 2, increase crude fiber; 3, reduce meat; 4, increase fresh fruits and vegetables; 5, avoid obesity. More specific recommendations are: 1, adults should maintain the body mass index (body weight in kilograms divided by height in meters squared) between 18.5 to 24.9, to avoid weight gain of more than 5 kilograms; 2, to maintain normal physical activity, sitting and working people should have a certain daily moderate-intensity physical activity, such as walking for 60 minutes a day, in order to maintain a healthy weight. More intense activities such as walking on an empty stomach may be beneficial for cancer prevention; 3. It is best not to drink alcohol. If needed it should be no more than 2 units per day; 4. Chinese-style salted fish should not be eaten more often, especially by children. The intake of salted food and salt should be moderate; 5. Minimize the contamination of food by aflatoxin; 6. At least 400g of fruits and vegetables should be consumed daily; 7. For those who are not vegetarians, it is better to limit the consumption of preserved meats (e.g. sausages, Italian sausages, cured meats, hams, etc.); 8. Don’t consume or drink foods and beverages at high temperatures. By establishing a healthy lifestyle, building awareness of cancer prevention, cutting off the channel between lifestyle and cancer, choosing a balanced diet, quitting smoking and limiting alcohol, increasing exercise and maintaining an optimistic mindset, we can prevent the occurrence of about 40% of “lifestyle cancer”.