Eating less may help you live longer, says a new study although scientists warn too much reduction could make life shorter.

In the 1930s it was found that laboratory animals fed a calorie-restricted diet lived longer and had a lower risk of cancer, diabetes and cardiovascular disease, but until now, there has been little evidence to suggest that calorie restriction diets extended human lives.

Now researchers, led by Andrew Dillin at the Salk Institute for Biological Studies in La Jolla, California, identified a gene in roundworms that directly links calorie restriction to a longer lifespan.

The research team found that the gene called 'pha-4' plays a role in gut development in embryonic worms, but in adults is associated with calorie-restricted longevity. Scientists say humans do have three genes very similar to pha-4.

These genes say the researchers are related to glucagon, a pancreatic hormone that increases blood sugar concentration and maintains the body's energy balance, particularly during fasting, reports the health portal News-Medical.

The researchers say the pinpointing of the worm gene might lead to drugs being developed that imitate the effects of calorie restriction and could allow people to live longer without following a severely restrictive diet.

Dillin says whether dietary restriction will increase longevity in humans is unclear but they are now testing the diet on monkeys.

The report is published in the current issue of the journal Nature.