Reassessment of the role of dietary fat in cancer etiology.

The role of dietary fat in cancer etiology is briefly discussed in terms of several major types of epidemiological evidence: geographic correlations, migrant studies, low-risk populations, and dietary modification trials. It appears that there is no conclusive evidence that lowering dietary fat intake will result in lowering the cancer death rate. Furthermore, it appears possible to have a relatively low death rate from "diet-related" cancers with an average fat intake. However, in order to fully assess the fat hypothesis, it is important to identify and carefully study a group of Americans with a genuine low-fat diet.