Based on current epidemiologic knowledge, public health recommendations to decrease total fat intake for the prevention of cancer appear largely unwarranted. Recommendations to decrease red meat intake, particularly processed meat or beef intake, may, on the other hand, decrease the risk of colorectal cancer and prostate cancer; it may have a beneficial effect on breast cancer as well, although the evidence is much less compelling in this regard. There appears to be no particular benefit regarding cancer prevention that would accrue from reducing fat intake from vegetable sources, and in the case of breast cancer, there is some suggestive but preliminary evidence that olive oil or other sources of monounsaturated fatty acids may modestly decrease risk. Overall, recommendations focused on controlling weight by regular physical activity and avoidance of excessive energy intake from all sources; increasing plant food intake; consuming a variety of whole grains, vegetables, and fruits; and decreasing red meat intake are likely to be more effective in decreasing risk of breast, colorectal, and prostate cancer than decreasing total fat intake. This conclusion is consistent with current recommendations for cancer prevention as promulgated by the American Cancer Society.