Maintaining a diet rich in plant-based foods while moderating the intake of healthy animal-based products and minimizing ultra-processed foods is associated with a higher likelihood of aging healthily, according to new research from Harvard T.H. Chan School of Public Health, the University of Copenhagen, and the University of Montreal.
The study, published in Nature Medicine, defines “healthy aging” as reaching 70 years of age without major chronic illnesses while maintaining cognitive, physical, and mental well-being. Unlike previous research that focused on diet’s impact on specific diseases or lifespan, this study provides a broader perspective on how dietary choices influence long-term independence and quality of life.
Dietary Patterns and Long-Term Health
Researchers analyzed data from over 105,000 men and women aged 39–69, drawn from the Nurses’ Health Study and the Health Professionals Follow-Up Study, over a span of 30 years. Participants regularly completed dietary questionnaires, which were evaluated based on their adherence to eight recognized healthy eating patterns:
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Alternative Healthy Eating Index (AHEI)
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Alternative Mediterranean Diet (aMED)
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Dietary Approaches to Stop Hypertension (DASH)
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Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND)
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Healthful Plant-Based Diet Index (hPDI)
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Planetary Health Diet Index (PHDI)
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Empirically Inflammatory Dietary Pattern (EDIP)
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Empirical Dietary Index for Hyperinsulinemia (EDIH)
Each of these diets prioritizes high consumption of fruits, vegetables, whole grains, nuts, legumes, and unsaturated fats. Some also include limited amounts of healthy animal-based foods, such as fish and dairy. Researchers also examined participants’ intake of ultra-processed foods—industrially manufactured products high in added sugars, sodium, artificial additives, and unhealthy fats.
Key Findings
Of the study participants, 9,771 (9.3%) were classified as aging healthfully. Those who closely followed any of the eight healthy dietary patterns had significantly higher chances of achieving healthy aging, with benefits spanning cognitive function, physical mobility, and mental well-being.
Among the dietary patterns, the AHEI stood out as the most effective. Participants in the highest quintile of AHEI adherence had an 86% greater likelihood of reaching 70 in good health and were more than twice as likely to maintain healthy aging through age 75 compared to those in the lowest quintile.
The AHEI emphasizes a diet high in fruits, vegetables, whole grains, nuts, legumes, and healthy fats while limiting red and processed meats, refined grains, sodium, and sugar-sweetened beverages. Another top-performing diet, the PHDI, focuses on both human and environmental health by promoting plant-based foods and reducing animal-based consumption.
Conversely, greater consumption of ultra-processed foods—especially processed meats, sugary drinks, and diet beverages—was linked to lower odds of healthy aging.
Public Health Implications
“Staying active and independent is a priority for both individuals and public health,” said co-corresponding author Marta Guasch-Ferré, an associate professor at the University of Copenhagen and adjunct professor at Harvard Chan School. “Our findings suggest that diets rich in plant-based foods, with moderate inclusion of healthy animal-based foods, can promote overall healthy aging and help shape future dietary guidelines.”
The study also highlights the flexibility of healthy eating. “There is no one-size-fits-all diet,” noted lead author Anne-Julie Tessier, an assistant professor at the University of Montreal and visiting scientist at Harvard Chan School. “Healthy diets can be adapted to fit individual needs and preferences.”
Limitations and Future Research
One key limitation of the study is that participants were exclusively health professionals, potentially limiting the generalizability of the findings. Researchers suggest future studies should examine populations with broader socioeconomic and ethnic diversity to strengthen the applicability of these conclusions.
Other Harvard Chan researchers involved in the study included Fenglei Wang, Heather Eliassen, Jorge Chavarro, Jun Li, Liming Liang, Walter Willett, Qi Sun, and Meir Stampfer.
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