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Pairing a Mediterranean-style eating pattern with modest calorie reduction, routine moderate exercise, and structured weight-loss support reduced the incidence of type 2 diabetes (T2D) by about 31% in a large, long-term clinical trial. Pairing the Mediterranean diet with exercise and calorie control cuts diabetes risk by nearly a third. Credit: Shutterstock
The findings come from PREDIMED-Plus, Europe’s largest randomized nutrition and lifestyle trial, and were published August 25, 2025, in the Annals of Internal Medicine. The analysis tracked nearly 4,800 participants for six years and offers high-quality evidence that three practical, scalable changes to diet and activity can produce measurable public-health benefits.
Study design and methods
Researchers from 23 Spanish universities and collaborators at Harvard T.H. Chan School of Public Health enrolled 4,746 adults aged 55–75 who were overweight or obese and had metabolic syndrome but did not have T2D at baseline. Participants were randomized into two arms:
Intervention group
- Followed a Mediterranean-style diet emphasizing fruits, vegetables, whole grains, legumes, nuts, olive oil, moderate dairy and lean protein, and limited red meat and processed foods.
- Reduced caloric intake by roughly 600 kcal/day compared with usual intake.
- Performed moderate physical activity such as brisk walking and targeted strength/balance exercises.
- Received professional support and counseling to help achieve and sustain weight loss.
Control group
- Followed the Mediterranean-style diet alone without calorie targets, structured exercise guidance, or professional weight-loss support.
The trial used standard diagnostic criteria for new-onset type 2 diabetes, repeated clinical visits and laboratory testing over a median follow-up of six years, and intention-to-treat analysis to estimate relative risk reductions.
Key findings and implications
Participants in the combined lifestyle intervention had a 31% lower risk of developing T2D than those who followed the Mediterranean diet only. Weight and central adiposity also improved more in the intervention arm: average weight loss was about 3.3 kg versus 0.6 kg in controls, and waist circumference decreased by 3.6 cm versus 0.3 cm.
From a population-health perspective, the authors estimated that adding calorie control, moderate physical activity and structured support to a Mediterranean diet prevented roughly three new cases of diabetes per 100 people over the study period. That effect size translates into substantial potential reductions in diabetes incidence when interventions are implemented at scale among at-risk populations.
Scientific context and mechanisms
The Mediterranean diet has been associated with lower cardiometabolic risk in many observational studies and trials. Its benefits are thought to stem from higher intakes of fiber-rich plant foods and unsaturated fats, improved lipid profiles, reduced systemic inflammation, and better insulin sensitivity. Calorie restriction and increased physical activity contribute to weight loss and reduce visceral fat — a key driver of insulin resistance — while behavioral counseling improves adherence and long-term maintenance.
Combining dietary quality with energy balance and structured support therefore targets multiple biological and behavioral pathways that underlie T2D development. The PREDIMED-Plus results strengthen causal evidence that modest, sustained lifestyle changes can alter disease trajectories in high-risk adults.
Expert Insight
"This trial gives us an actionable roadmap," says Dr. Elena Ruiz, nutrition epidemiologist at the Global Institute for Metabolic Health (expert commentary). "Improving diet quality is critical, but pairing that with achievable calorie goals, regular brisk walking, and professional or group support multiplies the benefit. For clinicians and health systems, the challenge is delivering these components affordably and equitably."
Dr. Ruiz adds that digital health tools, community exercise programs, and primary-care embedded counseling are promising delivery channels to translate these results into real-world prevention.
Related technologies and future directions
The trial underscores opportunities to integrate behavioral science, digital monitoring, and population health strategies:
- Digital apps and wearables can support adherence to activity targets and calorie tracking while providing data for remote counseling.
- Telehealth and group-based counseling reduce barriers to professional support in resource-limited settings.
- Implementation research can evaluate cost-effectiveness, equity, and long-term sustainability across diverse populations.
Further research should test adaptation of the PREDIMED-Plus approach in younger adults, non-European populations, and healthcare systems with different resource constraints, and explore biological mediators such as changes in visceral fat, inflammatory biomarkers, and insulin sensitivity.
Quotes from study authors
Co-author Frank Hu, chair of the Department of Nutrition at Harvard T.H. Chan School of Public Health, emphasized the global stakes: "We're facing a global epidemic of diabetes. With the highest-level evidence, our study shows that modest, sustained changes in diet and lifestyle could prevent millions of cases of this disease worldwide." Miguel Martínez-González, co-author and professor at the University of Navarra, noted the public-health framing: "In practical terms, adding calorie control and physical activity to the Mediterranean diet prevented around three out of every 100 people from developing diabetes — a clear, measurable benefit for public health."
Conclusion
The PREDIMED-Plus randomized trial provides robust evidence that three practical changes — adopting a Mediterranean-style diet, reducing calorie intake, and increasing moderate physical activity with structured support — lower the risk of developing type 2 diabetes by roughly 31% in older adults with overweight/obesity and metabolic syndrome. These findings support integrated dietary, exercise and behavioral strategies as scalable components of diabetes prevention programs and highlight opportunities for technology-enabled delivery and broader implementation research.
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