Researchers discovered reducing calories over a longer period of time slows the pace of aging by between 2% and 3% in healthy adults, which may lower risk of death, a new study finds.
“It provides a proof of concept that a behavioral intervention, like caloric reduction, can actually have a measurable impact on the pace of aging,” says Dr. Calen Ryan, co-lead author on the study and scientist at the Butler Columbia Aging Center in the Mailman School of Public Health.
The study, published in the journal Nature Aging and funded by the U.S. National Institute on Aging, examined the effects of calorie reduction on non-obese humans over two years. Researchers from the Butler Columbia Aging Center followed over 200 men and women in the U.S. A majority of the participants were asked to reduce caloric intake by 25%, while the rest followed a standard controlled diet.
Researchers analyzed participants’ blood samples to understand the slope, or progression, of aging using a number of physiological markers, like organ system integrity and typical measurements you receive at a doctor’s checkup. They took samples before the study began, at one year, and again at two years.
The results remained significant, despite not everyone in the reduction group achieving the 25% restriction, Ryan tells Fortune.
“Even given the levels of caloric restriction that they did achieve, we still saw changes in the pace of aging, which starts to open up the door to potentially other…behavioral interventions,” he says.
Previous studies on animals have found an association between calorie reduction and slowing the pace of aging, as well.
One recent two-year study in humans published in the journal Immunity found moderate calorie restriction (14%) reduced the production of a protein called SPARC that can cause inflammation that can reduce lifespan. Longer-term research is still underway.
Calorie restriction has its limitations
Adhering to a strict diet is not feasible for everyone, and for many, it can be harmful if they are struggling with their relationship with food, diet, or exercise. Ryan says the participants were guided by doctors and nutritionists who ensured they had a complete, nutritious diet regardless of which group they were in.
“This is a safe reduction in calories while maintaining a healthy, nutritious diet,” he says. “Undernutrition will have just as many negative effects on health and aging as over nutrition,” adding that going beyond reduction into complete restriction has the opposite effect on the pace of aging.
There’s no specific calorie goal guaranteed to lengthen your life—and the researchers did not specify a certain calorie count. However, consuming a diet rich in ultra-processed foods and lower in protein and fiber has been associated with heart problems that can lead to mortality. Instead, most medical professionals recommend diets that prioritize whole, minimally-processed foods with a myriad of nutrients as a way to take control of your health without cutting calories or under-eating.
While the results of the randomized trial show a correlation between diet and the pace of aging, this type of intervention might not be for everyone.
“Reducing the intake of calories [and] safely maintaining healthy nutrition, even if you have the support of a nutritionist and a doctor, can be quite challenging,” Ryan says. “Nevertheless, this study does provide the proof of concept that behavioral interventions that people are capable of doing with that support can still have an effect on the pace of aging.”
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