Cutting down the amount you eat could help you live up to 18 years longer, a study suggests.
Researchers say having fewer calories in your diet as an adult can lead to a longer and healthier life.
But cutting the amount of food at a younger age is not beneficial.
Experts analyzed data from two separate studies involving almost 200 rhesus monkeys.
And they say the results should also apply to humans.
They found adult monkeys who received 30 percent less food tended to live up to two years longer for males and almost six years longer in females.
If similar results could be seen proportionally in humans, it could extend people’s lives for up to 18 years.
But the researchers said in the real world the effect would likely be less.
Study leader Dr. Julie Mattison, from the National Institute on Aging, a division of the Department of Health, said other aspects of lifestyle would have an impact on how long a person could live.
She added: “The outcomes of these studies are translatable to humans but the information needs to be considered in the context of many things.”
Scientists have been divided over whether restricting calories could have a noticeable impact on human lifespan after studies in monkeys showed contradictory results.
Studies using mice had suggested cutting the amount of food they eat could result in dramatic increases in lifespan.
A study in 2009 from the University of Wisconsin-Madison showed adult monkeys lived longer and suffered less cancer, heart disease, and insulin resistance if they ate less.
But a second study in 2012 showed there was no improvement in survival.
The researchers have now found that the reason for the difference is because eating less seems to be beneficial in adult animals but not younger primates.
Writing in the journal Nature Communications, they said it seems feeding the monkeys healthier diets rather than processed “junk food” also seemed to make a difference.
Mattison added: “We can use this to begin to understand the mechanisms of the calorie restriction effect on health and the aging process.
“But it may not be reasonable to use them to prescribe a calorie restriction regimen that people should follow.”
“Calorie restriction in humans is still an experimental concept and there are initial studies underway.”