Which Diet Holds the Secret to a Long Life?

As the global population grows older, the goal is not only to prevent disease but also to maintain cognitive, physical, and mental health in later life. A striking study published on March 24, 2025, in Nature Medicine examines the dietary habits of more than 105 thousand participants followed for many years, focusing on the relationship between their eating habits and “healthy aging.”

The results are clear: diets emphasizing unprocessed plant foods and moderate consumption of animal foods help people live longer while preserving their health in later life.

Healthy Aging over 30 Years of Follow-Up: Only 9.3%

Researchers examined data from two US studies, the Nurses' Health Study and the Health Professionals Follow-Up Study, between 1986-2016. Only 9.3% of the total 105,015 participants (9771 people) met the criteria for “healthy aging.”

Criteria for Healthy Aging:

• Living to age 70,

• Remaining free of 11 chronic diseases (cancer, cardiovascular disease, diabetes, etc.),

• Having no impairment in cognitive, physical, or mental functioning.

What Are the 11 Major Chronic Diseases?

1. Cancer (excluding nonmelanoma skin cancers)
2. Type 2 diabetes
3. Myocardial infarction (heart attack)
4. Coronary artery disease (ischemic heart disease)
5. Congestive heart failure
6. Stroke (cerebrovascular disease)
7. Kidney failure
8. Chronic obstructive pulmonary disease (COPD)
9. Parkinson's disease
10. Multiple sclerosis (MS)
11. Amyotrophic lateral sclerosis (ALS)

Which Diets Are More Effective?

Eight different dietary patterns were examined:

1. AHEI (Alternative Healthy Eating Index)

This diet was developed on the basis of scientific evidence, focusing on reducing chronic disease risk. It recommends whole grains, fruits and vegetables, nuts, polyunsaturated fats, and fish, while limiting trans fats, red and processed meat, and sugary drinks.

2. aMED (Alternative Mediterranean Diet)

An American version of the traditional Mediterranean diet. It is based on foods such as olive oil, fish, vegetables, fruit, legumes, and nuts, while minimizing red meat and processed foods. Small amounts of red wine may also be included in this pattern.

3. DASH (Dietary Approaches to Stop Hypertension)

Focuses on lowering blood pressure. Sodium and salt restriction is emphasized; vegetables, fruit, whole grains, and low-fat dairy products are recommended. Red meat, sugary drinks, and saturated fats are limited. It is a reduced-salt Mediterranean diet.

4. MIND (Mediterranean-DASH Intervention for Neurodegenerative Delay)

A dietary pattern protective against Alzheimer's and other neurological diseases. It emphasizes leafy green vegetables, blueberries, whole grains, nuts, and olive oil. Fried foods, butter, cheese, and sugary desserts are reduced.

5. PHDI (Planetary Health Diet Index)

Focuses on both human health and environmental sustainability. Plant proteins (legumes and nuts), fruit, vegetables, and whole grains are emphasized. Animal foods and foods associated with high greenhouse gas emissions are minimized.

6. hPDI (Healthful Plant-Based Diet Index)

A diet that scores healthy plant foods—fruit, vegetables, whole grains, nuts, and legumes—positively, and unhealthy plant foods such as white bread and French fries, along with animal products, negatively. It recommends predominantly plant-based eating rather than veganism.

7. EDIP (Empirical Dietary Inflammatory Pattern)

A scoring system based on blood inflammatory markers such as CRP and IL-6. Foods such as sugary drinks, red meat, and processed grains increase inflammation, while tea, coffee, vegetables, and fruit have a reducing effect.

8. EDIH (Empirical Dietary Index for Hyperinsulinemia)

Developed based on how foods affect the body's insulin response. Refined carbohydrates, sugary foods, and animal fats increase the score, while whole grains, vegetables, and plant oils reduce the insulin response and lower the score.

Greater adherence to each of these dietary patterns increased the likelihood of healthy aging. The strongest association was found with the AHEI diet: using an age threshold of 75, the likelihood of healthy aging increased 2.24-fold.

Overall Results for All 105,015 Study Participants

Data summary:

• Reached age 70: 37.9%

• Remained free of the 11 diseases: 22.8%

• Preserved cognitive function: 33.9%

• Preserved physical function: 28.1%

• Preserved mental health: 26.5%

What Should Your Diet Look Like?

Foods associated with healthy aging:

Positive effects: Fruit, vegetables, whole grains, nuts, legumes, healthy fats (including olive oil), and low-fat dairy products

Negative effects: Trans fats, sodium, processed meats, and sugary drinks

In addition, consumption of ultraprocessed foods (instant soups, packaged snacks, etc.) was associated with a 32% lower likelihood of healthy aging.

The heat map aboveshows the effect of differences in consumption between the 90th and 10th percentiles on healthy aging. Green squares represent positive associations and pink squares negative ones. Darker colors indicate stronger effects. All analyses were adjusted for many factors, including age, sex, BMI, smoking, alcohol, physical activity, socioeconomic status, and history of depression. Asterisks (*) indicate statistically significant findings.

There Is No Single Diet for Everyone

Study author Dr. Anne-Julie Tessier comments: “Diets rich in olive oil, whole grains, vegetables, and fruit are generally the most beneficial. However, people's cultural preferences, financial circumstances, and protein needs may differ as they age."

Dr. Tessier describes her own diet as follows: "Most of my plate consists of fruit and vegetables; I include whole grains, legumes, small amounts of fish and yogurt, and use olive oil for cooking."

Clinical Recommendation: Adherence Matters Most

The best dietis a plant-based diet a person can follow over the long term. A nutrition plan should focus not only on old age but also on quality of life. It should also be supported by physical activity.

Conclusion: A Planet-Friendly Diet Is Directly Associated with Longevity

This study shows that models such as the Planetary Health Diet, which protect both health and the environment, offer benefits for individuals and the planet alike. Varied, natural, balanced nutrition forms the basis of healthy aging.