Eating too much fat can also put you at risk of developing certain cancers. A recent study by the World Cancer Research Fund and the American Institute for Cancer Research found that a lack of good nutrition and physical activity are proven risk factors for certain cancers. The study also provided dietary recommendations. For example, because diets high in red meat are a risk for developing colon cancer, experts recommend eating no more than 18 ounces per week (preferably less), and avoiding processed meats that are smoked, salted, cured, or contain chemical preservatives.

The report does not advise eliminating meat altogether, but recommends a diet low in red meat and high in non-starchy vegetables, fruits, and whole grains. And it emphasizes that a low-fat diet combined with a healthy weight and regular exercise can reduce your risk of several cancers, including those of the breast, colon, esophagus, kidney, and pancreas.

Women are more prone to breast and ovarian cancers when they have a family history, genetic factors, and have experienced previous cancers, but new evidence suggests that diets high in fat may be another risk factor for post-menopausal women. For example, 2007 findings from the Women's Health Initiative, a large, long-term study dedicated to major health conditions affecting nearly 49,000 postmenopausal women, show that women who ate a low-fat diet had fewer new cases of ovarian cancer than women who had higher-fat diets. And findings from the National Institute of Health and the American Association of Retired Persons combined study of nearly 189,000 postmenopausal women found that women who had higher-fat diets, especially those high in saturated fats, had an increased risk for breast cancer.

These studies don't claim that fats alone cause cancer, but they do demonstrate that high-fat diets can be a risk factor.