Study Highlights the Potential Link Between Diet and Healthy Aging

A person’s chronological age increases steadily over time, but biological age may tell a different story. Biological aging reflects how well the body is functioning internally and can vary significantly from person to person depending on genetics, lifestyle, stress, physical activity and diet. Now, new research suggests that dietary changes may influence biological aging markers in older adults in as little as four weeks.

A team of investigators analyzed data from the Nutrition for Healthy Living study, which included 104 adults between the ages of 65 and 75. Participants were randomly assigned to follow one of four diets for four weeks: an omnivorous high-fat diet, an omnivorous high-carbohydrate diet, a semi-vegetarian high-fat diet or a semi-vegetarian high-carbohydrate diet.

To estimate biological age, investigators used the Klemera-Doubal Method, which combines multiple biomarkers related to health and aging into a single measurement. Researchers specifically examined “delta age,” the difference between a person’s biological age and their chronological age. A lower delta age suggests healthier biological functioning relative to a person’s actual age.

The study, published in Aging Cell, found that participants following the omnivorous high-fat diet — which most closely resembled the diets participants were already eating before the study — showed little to no meaningful improvement in biological age markers. However, participants who switched to an omnivorous high-carbohydrate diet experienced significant reductions in their biological age measurements over the four-week period.

Similarly, participants following the semi-vegetarian diets, whether higher in fat or carbohydrates, also showed improvements in biological age markers compared to the omnivorous high-fat group, although some of these changes were not statistically significant.

Investigators say the findings suggest that the body may respond fairly quickly to dietary changes, potentially improving physiological markers linked to aging and overall health. However, the investigators emphasize that these results should be interpreted carefully.

“Longer-term dietary changes are needed to assess whether dietary changes alter the risk of age-related diseases,” said Alistair Senior, Ph.D., an associate professor from the School of Life and Environmental Sciences at the University of Sydney and the Charles Perkins Centre, who supervised the research.

Importantly, the study does not prove that diet can literally “reverse aging.” Instead, the team says the observed changes may reflect short-term improvements in how the body responds to healthier dietary patterns, rather than permanent changes to the aging process itself.

The findings do reinforce the growing understanding that nutrition plays an important role in healthy aging. Diets emphasizing plant-based foods, balanced macronutrients and healthier eating patterns may positively influence inflammation, metabolism, cardiovascular health and other biological systems involved in aging.

For patients, the study offers another reminder that it may never be too late to make meaningful dietary changes. While no single diet can stop aging, healthier nutrition choices may help support better physical function, resilience and overall well-being later in life.

“It’s too soon to say definitively that specific changes to diet will extend your life,” noted lead investigator Caitlin Andrews, Ph.D., from the University of Sydney’s School of Life and Environmental Sciences. “But this research offers an early indication of the potential benefits of dietary changes later in life. Future research should explore whether these findings extend to other cohorts and whether the changes recorded are sustained or predictive of long-term outcomes.”