Eating healthy linked to healthy aging

a close up of a persons hands getting ready to eat salad

Published July 1, 2026

At a glance

Healthy eating in midlife was associated with healthier aging in a long-term study of more than 105,000 adults.
Researchers examined several dietary patterns and later physical, cognitive and mental health, rather than focusing only on lifespan.
Plant-rich patterns and lower ultraprocessed food intake featured in the findings. The study reports associations and allows for different healthy eating patterns, rather than identifying one diet for everyone.

Maintaining a healthy diet rich in plant-based foods, with low to moderate intake of healthy animal-based foods and lower intake of ultra-processed foods, was associated with a higher likelihood of healthy aging in a long-term observational study.

The study, conducted by researchers from Harvard T.H. Chan School of Public Health, University of Copenhagen, and University of Montreal, concludes that such a diet is linked to a higher likelihood of healthy aging, which is “defined as reaching age 70 free of major chronic diseases and with cognitive, physical, and mental health maintained.”

According to a release issued on March 24, 2025, the study is among the first to examine multiple dietary patterns in midlife in relation to overall healthy aging.

“Studies have previously investigated dietary patterns in the context of specific diseases or how long people live. Ours takes a multifaceted view, asking, how does diet impact people’s ability to live independently and enjoy a good quality of life as they age?” said Frank Hu, chair of the Department of Nutrition at Harvard Chan School.

The study, published in Nature Medicine on March 24, 2025, examined the midlife diets and eventual health outcomes of more than 105,000 women and men ages 39-69 over the course of 30 years.

Participants, the release stated, regularly completed dietary questionnaires, which the researchers scored on how well participants adhered to eight healthy dietary patterns: the Alternative Healthy Eating Index (AHEI), the Alternative Mediterranean Index (aMED), the Dietary Approaches to Stop Hypertension (DASH), the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND), the healthful plant-based diet (hPDI), the Planetary Health Diet Index (PHDI), the empirically inflammatory dietary pattern (EDIP), and the empirical dietary index for hyperinsulinemia (EDIH).

Each of the diets, it added, “emphasizes high intake of fruits, vegetables, whole grains, unsaturated fats, nuts, and legumes, and some also include low to moderate intake of healthy animal-based foods such as fish and certain dairy products. The researchers also assessed participants’ intake of ultra-processed foods, which are industrially manufactured, often containing artificial ingredients, added sugars, sodium, and unhealthy fats.”

The study found that 9,771 participants—9.3% of the study population—aged healthfully. Adhering to any one of the healthy dietary patterns was linked to overall healthy aging and its individual domains, including cognitive, physical, and mental health.

Higher intake of ultra-processed foods, especially processed meat and sugary and diet beverages, was associated with lower chances of healthy aging.

“Since staying active and independent is a priority for both individuals and public health, research on healthy aging is essential,” said co-corresponding author Marta Guasch-Ferré, associate professor in the Department of Public Health at the University of Copenhagen and adjunct associate professor of nutrition at Harvard Chan School.

“Our findings suggest that dietary patterns rich in plant-based foods, with moderate inclusion of healthy animal-based foods, may promote overall healthy aging and help shape future dietary guidelines.”

Lead author Anne-Julie Tessier, assistant professor in the Department of Nutrition at the University of Montreal, researcher at the Montreal Heart Institute, and visiting scientist at Harvard Chan School said the findings “also show that there is no one-size-fits-all diet. Healthy diets can be adapted to fit individual needs and preferences.”

What this means for readers over 50

The study connects eating patterns in midlife with later physical, cognitive and mental health, rather than looking only at lifespan. For readers over 50, it provides context for thinking about food choices alongside the goal of staying independent as they age. It does not establish one diet that will work for everyone. In What Hunger Taught Me About Aging, Andrew Bowins describes how a nutrition conversation during cardiac rehabilitation prompted his own questions; that essay is personal experience, rather than evidence of a treatment effect.

What the study cannot tell us

This was an observational study: the findings show associations, not proof that a particular diet caused healthier aging. Participants were health professionals, so the results may not apply equally to people from other backgrounds. The researchers noted that further studies in more diverse populations would help clarify how widely the findings apply.