Aging sucks. Just when you hit your prime, things you take for granted—like grip strength, hormone levels, and energy—start to decline.
To make things worse, there are a million and one tricks and products that claim to boost longevity, but few have the scientific research to back up their claims.
Calorie restriction isn’t on the list. Restricting calories appears to slow the pace of aging and increase longevity in adults, according to the results of a new study published in Nature Aging (1).
The study, which was funded by the National Institutes of Health (NIH), is the first-ever randomized controlled trial that looked at the long-term impact of calorie restriction.
“It is possible to slow the pace of biological aging and it may be possible to achieve that slowing through modification of lifestyle and behavior,” the study’s senior author, Dan Belsky said.
The key take-home: “We all have the power to change the trajectories of aging,” said Dr. Evan Hadley, director of geriatrics and clinical gerontology division at the National Institute of Aging.
How does it work?
What Did the Research Show?
The phase 2 clinical trial followed 220 healthy adults ranging in body mass index (BMI) from 22 to 27. The adults were randomized to either cut their calories by 25 percent or make no change to their existing diet.
People in the calorie-restricted group were given prepared meals every day for the first month, as well as behavioral counseling for the first six months. The participants who stuck to their regular diets didn’t receive meals or counseling.
The scientists followed the participants for two years, taking blood samples at the start of the study, and again at 12 and 24 months. To measure the rate of aging, they used an algorithm to see how certain DNA markers in the blood changed over time.
Based on the blood test results, the researchers found those who cut their calories slowed the pace of aging by two to three percent, compared to people who followed a normal diet. That translates to a 10 to 15 percent reduction in the likelihood of early death.
Plus, most people in the calorie-restriction group only ended up cutting their daily intake by about 12 percent, according to Hadley. “But that 12% was enough to have significant changes,” he added.
It’s not yet known whether the slow in aging would hold after the two years, but he noted a separate study is in the works which plans to track the results of a calorie-restricted diet after 10 years.
Calorie Restriction and Healthy Aging
Researchers still don’t know exactly why cutting calories may slow aging, but the results of the study are evidence that it initiates change on the cellular level.
“It may induce sort of mechanisms of survival response in the body that have the effect of cleaning up intracellular garbage,” Belsky said. “It’s a signal to the body, saying ‘Hey, pay attention. There are resource stresses in the environment. We need to make sure that we are using all of the resources available to us most efficiently.’”
This new study reinforces findings from previous research that calorie restriction can promote health benefits, including improving health and lifespan.
One study published in August 2022 in Immunity found that moderate calorie restriction in people reduces the production of a protein called SPARC, which in turn reduces inflammation (2). A recent review suggests caloric restriction plays a significant role in delaying frailty and sarcopenia, a risk of aging in older adults (3).
Hadley cautioned against overinterpreting the results, warning that calorie restriction may not be for everyone, including those with multiple underlying conditions. “It’s not like this is somehow this universal key to aging, it’s going to slow everything down,” he said. He suggests talking to a doctor before restricting calories.