The study, published in the journal Prostate, found mice fed a low-fat but high-carbohydrate diets had larger tumors. The mice on a diet high in both fat and carbohydrates had the biggest tumors and the worst survival rates.

"This study showed that cutting carbohydrates may slow tumor growth, at least in mice," lead researcher Dr. Stephen Freedland, of Duke University Medical Center, in Durham, N.C., said in a statement. "If this is ultimately confirmed in human clinical trials, it has huge implications for prostate cancer therapy through something that all of us can control, our diets."

The researchers hypothesized carbohydrates in the diet affect the levels of serum insulin and a related substance known as insulin-like growth factor in the body.

Since earlier research has already linked the growth of prostate tumors to higher levels in insulin-like growth factor in the mice, the researchers tested whether the reduction in the levels of these substances in mice -- through diet -- might slow tumor growth. They found only the mice on the low-carbohydrate diet had lower levels of the form of insulin-like growth factor capable of stimulating tumor growth.