A low-protein, low-calorie diet might prevent the development of some cancers, according to Washington University School of Medicine in St. Louis researchers. Previous research has established that being overweight increases breast cancer, endometrial cancer, colon cancer, kidney cancer, prostate cancer and esophageal cancer risks but this research indicates findings to suggest that a low-protein, low-calorie diet offers protection in addition and independent of a healthy weight.

What you are eating seems to be as important as how much you eat.

A low-protein, low-calorie diet lowers the levels of a plasma growth insulin-like factor called IGF-1 and hormones responsible for increased cancer risks. High levels of IGF-1 is associated with some cancers and cell proliferation.

The participants in the study were divided into three groups: low-protein, low-calorie, raw food vegetarians; endurance runners who ate a diet higher in calories and protein than the vegetarians; and sedentary people who consumed a diet rich in sugars, processed refined grains and animal products.

Not surprisingly, the sedentary group fared the worst in IGF-1 and hormone levels. However, because exercise is known to provide a cancer prevention benefit, it is a little surprising that the endurance runners had higher levels of IGF-1 and hormone levels that increase the risk of cancer. This has led researchers to the conclusion that the amount of protein and calories consumed plays a greater role than exercise alone in offering optimum cancer prevention.

"Many people are eating too many animal products - such as meat, cheese, eggs and butter - as well as refined grains and free sugars," states Luigi Fontana, M.D., Ph.D., assistant professor of medicine at Washington University. "Our intake of vegetables and fruits is low, and beans are vastly underconsumed in the U.S. and Europe these days. We hope to further clarify what happens to cancer risk when we are chronically eating more protein than we need."