BAKERSFIELD, Calif. -- A new study from the Preventive Medicine Research Institute in California has found that men with early stage prostate cancer altered more than 500 of their genes by engaging in regular exercise, stress reduction, and following a very low fat diet.

Current government recommendations call for a diet that is less than 30 percent fat, but many Americans consume even more.

For this study, men cut their fat to just 10 percent -- they ate a vegetarian diet with daily tofu and protein supplements, but no cooking oils.

The results? After three months, tests showed decreased activity in master cancer genes that trigger tumor growth and increased activity in cancer-fighting genes.

The authors say these DNA changes would likely benefit many kinds of cancer patients, including breast cancer.

However, most doctors have said they would like to see a larger, longer study before they sign off on the diet.