Smoking and drinking alcohol can cause some people to get certain types of cancer. These cancers might be prevented by avoiding tobacco and alcohol. The best idea is to never use tobacco at all. Cigarettes, cigars, pipes and even smokeless tobacco cause cancer. People who already smoke should try to quit.

Some recommendation for preventing cancer includes:

Eat a variety of healthful foods, with an emphasis on plant sources.
Overweight/obesity increases the risk for cancers
Eat foods as close to their natural state as possible. Choose predominantly Plant based diets rich in fruits and Vegetables
Eat 400-800 grams a day of a variety of vegetables and fruits
Choose whole grains in preference to processed (refined) grains and sugars.
Limit consumption of salted foods and use of cooking oil. Store perishable foods in ways that minimize fungal contamination.
Limit consumption of fatty foods. Choose modest amounts of vegetable oils
Limit consumption of red meats, especially those high in fat and processed. Do not eat charred food.
Adopt a physically active lifestyle. Balance caloric intake with physical activity.
Avoid alcoholic beverages and tobacco