Washington, May 14 (IANS) A low-calorie diet is likely to be better than regular exercise or aerobics in extending one’s lifespan, according to a study. “We know that being lean rather than obese is protective from many diseases, but key rodent studies tell us that being lean from eating less, as opposed to exercising more, has greater benefit for living longer,” said Derek M. Huffman of Albert Einstein College of Medicine and the study’s lead author.

Although the study applies only to rodents, at least two studies which examined people engaging in high-volume exercise versus people who restricted calorie intake, had a similar outcome: caloric restriction has physiological benefits that exercise alone does not.

Researchers expect that clues to the physiology of longevity in mice will eventually be applied to people, Huffman said.

Two previous studies showed that rats that exercise regularly will, on average, live longer compared to a group that eats the same amount but does not exercise. This is because exercise prevents some diseases, which allows more individual animals to live out their expected life span.

However, when comparing the rats in these two groups that eat the same amount, the longest-lived animals in the exercise group don’t live any longer than the longest-lived rats in the non-exercise group.

Taken together, these findings indicate that exercise can prevent an early death from disease in some rats, but does not extend the maximal lifespan of any of the rats.

When comparing rats that exercise to those that don’t exercise but eat much less, the longest-lived rats are from the group that ate less.

Taken together, these findings indicate that caloric restriction protects against disease better than exercise does, and has the added benefit of extending the life span of some rats.

Huffman also emphasised that the benefits of exercise may be greater for humans than for mice because people are more prone to develop cardiovascular diseases, and exercise is particularly good at warding off those diseases. Mice tend to die of kidney disease and cancer, Huffman said.

The findings of the study appear in the latest issue of the American Journal of Physiology.