February 14, 2023 — According to a brand new study, if we reduce the variety of calories we eat by 25%, we will slow our aging process by 2 to three%. That may appear to be a small profit for an enormous calorie reduction. But experts say it's actually a reasonably large deal.
“In other studies, the same difference in the rate of aging had important consequences for people's risk of death,” says lead study creator Daniel W. Belsky, PhD, a researcher on the Butler Columbia Aging Center at Columbia University Mailman School of Public Health in New York City.
A 25% reduction in calorie intake slowed the aging process in young and middle-aged adults by several percentage points in comparison with individuals who continued to eat a traditional weight loss program, latest research shows. This first-of-its-kind study in humans adds to evidence from animal studies that the aging process will be influenced.
Compared to 75 individuals who ate a traditional weight loss program, the 145 people within the randomized controlled trial who were randomly assigned to cut back their calorie intake slowed their aging process by 2 to three percent over a two-year period.
For example, in previous studies, an analogous slowing of the aging process has been linked to a ten to fifteen percent lower risk of death over a ten to 15-year period, Belsky says. “So aging 2 to 3 percent slower may not sound that big – but a 10 to 15 percent reduction in the risk of death seems like a big deal.”
The results of the study were published last week within the journal Natural aging.
Although the aging process slowed, the researchers of their study found no significant changes in two biological aging parameters, suggesting that further research is required.
The results “are intriguing in that calorie restriction appears to slow aging in healthy adults,” says Vandana Sheth, a registered dietitian and owner of a nutrition consulting firm in Los Angeles. “This may have significant implications for population health. However, larger studies need to be done to verify these findings.”
“Exciting result”
When asked if the outcomes suggest that the aging process might be slowed in humans, Belsky said, “That's the … exciting result of the study. These results suggest that it may be possible to slow the biological aging process through a behavioral intervention.”
But not everyone seems to be completely convinced.
“This is a good indication that calorie restriction can alter aspects of biological aging in humans, similar to what has been known in laboratory animals for many decades,” says Matt Kaeberlein, PhD, director of the Healthy Aging and Longevity Research Institute on the University of Washington in Seattle and senior creator of “Anti-aging diets: separating fact from fiction”, a Review article 2021 In Science.
Among other things, he fears that reducing calorie intake by a quarter may not be a sustainable strategy in the long term.
“It is essential to do not forget that these measures only reflect a portion of biological aging and are likely not an accurate overall measure of biological age or biological aging rate,” Kaeberlein says. The results may suggest that “on the population level, a 25 percent reduction in calorie intake is unlikely to have a big impact on biological aging unless it's implemented over a few years, which might be not meaningful for most individuals.”
Insights into intermittent fasting?
Reducing calorie intake is linked to other dietary strategies, including intermittent fasting and time-restricted eating, Belsky says. “Intermittent fasting and time-restricted eating are dietary interventions that were developed, partly, because they've a few of the same biological effects as calorie restriction in animal studies.”
Many questions are still unanswered.
“There are individuals who argue that the rationale calorie restriction works is because individuals who restrict their calories also are inclined to restrict their eating times,” says Belsky. “They are inclined to have longer fasting periods through the day.”