Rationing food intake every few weeks could slash men's risk of prostate cancer, scientists believe.
Men who halve the amount they normally eat for a week or two once a month could markedly lower their chances of a tumour at a young age. Animal studies carried out at the University of Minnesota showed wartime eating habits significantly delayed the onset of cancer.
In human terms, researchers said, it was the equivalent of men getting cancer in their seventies or eighties rather than their fifties. But the study showed going on a permanent low-calorie diet did not have the same powerful effect. Scientists think occasional rationing may ward off cancer by constantly adjusting the balance of certain fat hormones.
High levels of leptin, a hormone released by fat cells, have been found to stimulate cancer cell growth, while high levels of another hormone, called adinopectin, appear to have a protective effect. The latest findings, published in the journal Prostate, suggest frequent rationing cuts leptin levels and boosts those of adinopectin.
Several other studies have suggested limiting calories could be crucial to good health and a longer life.
In 2004, experts at Harvard Medical School in Boston, found women who regularly rationed their food were half as likely to get breast cancer as those who always ate until they were full.
More recently, researchers studying daughters of women caught in the Dutch famine of 1944-45 found they were more fertile and had a higher number of pregnancies than those born to mothers with better food supplies.
In Australia, meanwhile, scientists have recently embarked on a clinical trial to see if depriving cancer patients of food for a couple of days before chemotherapy treatment can protect the body against its toxic effects.