Western diets are high in fats compared to Oriental ones, and a 20 fold difference in colorectal cancer incidence exists between East and West. Consequently, fats have been suspected as the main culprit in colorectal cancer.
The scientific evidence is by no means clear cut. A large scale report, Food, Nutrition and the Prevention of Cancer the result of three years of work by 2,250 scientists evaluating 4,500 research studies implicated meat itself in colon and rectal cancer (Am J Epidemiol, 1990; 132: 783). However, in a more recent survey of the epidemiological evidence to date, nutritionists at Harvard Medical School could find no link between total fat intake and colon cancer. They reported that "red meat or beef has been related to colon cancer risk in most studies, whereas dietary fat from sources other than red meat, including dairy, poultry and vegetable oils, does not increase the risk of colon cancer". Nevertheless, the Harvard researchers said that the risk didn't seem to be caused by its total fat content.This suggests, they wrote, "that other factors such as heterocyclic amines formed during cooking may be critical" (Am J Clin Nutr, 1997; 66: 1564S-71S). However, a more recent widescale US study could find no correlation with cooked meats, but it did uncover a weak link between processed meat and increased risk of colon cancer (Cancer Epidemiol Biomarkers Prev, 1999; 8: 15-24).