Study: restricted calorie diet may not fight aging

Dieters looking for the key to a long life span often turn to a sharply restricted calorie count but a new study on rhesus monkeys is putting the benefits of a low calorie lifestyle in question. 

The study showed that monkeys who were fed a very low calorie diet saw health benefits but didn't live any longer than their high-calorie brethren, undermining the belief that restricted calorie diets can help people live longer, reports the Wall Street Journal. 

The results conflict with an often-cited 2009 study that showed monkeys on an -extra low calorie diet lived longer than those that ate more. 

The earlier study was the first time a low calorie diet was proven to increase longevity in primates instead of just lab rodents, reports Wired magazine. The results raised hopes that people could add extra years to their life just by restricting their calories. 

"From the beginning, there have been people who were true believers in the effects of calorie restriction in every single species," Rafa de Cabo, a National Institute on Aging gerontologist and co-author of the new study, told Wired.

"Often attention wasn't paid to data showing that in some cases calorie restriction wasn't good, or didn't produce the effects it should have."

Decades of experiments on lab rats have shown that restricting calories can increase longevity by 30 to 40 percent, and people have been trying to replicate that success by eating as much as 30 percent below the typical daily calorie intake of 2,200, reports the Wall Street Journal. 

Scientists with the National Institute on Ageing were surprised to find that calorie restriction did not affect the monkey's life spans, according to The Washington Post. 

The monkeys didn't live any longer than those in a control group but did see some health benefits including lower rates of cancer and diabetes. 

Matt Kaeberlein, a scientist at the University of Washington, told the Washington Post it was too early to dismiss calorie restriction entirely. “There are still reasons to be optimistic that caloric restriction or drugs mimicking its beneficial effects will enhance healthy aging in people,” he said.