Studies suggest that differences in diet may also play a role in determining cancer risk. Unlike clear-cut cancer risk factors such as tobacco, sunlight, and alcohol, dietary components that influence cancer risk have been difficult to determine. Limiting fat consumption and calorie intake appears to be one possible strategy to decrease risk for some cancers, because people who consume large amounts of meat, which is rich in fat, and large numbers of calories exhibit an increased cancer risk, especially for colon cancer.