The Mediterranean diet is already well-known for its positive effects on the heart and metabolism. But a large clinical trial in Spain suggests it could be even more effective against type 2 diabetes when combined with three practical upgrades: eating fewer calories, getting more exercise, and getting professional help with weight loss.
The PREDIMED-Plus trial found that this more structured Mediterranean lifestyle reduced the risk of developing type 2 diabetes by 31%. The project is the largest nutrition trial conducted in Europe and involves more than 200 researchers from the University of Navarra and 22 other Spanish universities, hospitals and research centres. The initiative was implemented in more than 100 primary care centers within Spain’s national health system.
A smarter version of the famous diet
PREDIMED-Plus began in 2013 after the University of Navarra received an advanced grant of over 2 million euros from the European Research Council (ERC). More institutions participated between 2014 and 2016, bringing the total funding amount to over €15 million. Most of that support was provided by the Carlos III Institute for Health Research (ISCIII) and the Biomedical Research Network Center through the fields of Physiology of Obesity and Nutrition (CIBEROBN), Epidemiology and Public Health (CIBERESP), and Diabetes and Related Metabolic Diseases (CIBERDEM).
The results, published in the Annals of Internal Medicine, were based on 4,746 adults aged 55 to 75. All were overweight or obese and had metabolic syndrome, but none had diabetes or cardiovascular disease at the start of the study. Researchers followed participants for six years to see if a more intensive Mediterranean-based lifestyle plan provided a stronger protective effect against type 2 diabetes than the traditional Mediterranean diet alone.
One group followed a low-calorie Mediterranean diet (about 600 calories less per day), added moderate physical activity (brisk walking, strength training, balance training), and received expert guidance. The comparison group followed a traditional Mediterranean diet without calorie restriction or exercise advice.
Big diabetes prevention with small changes
The differences between the two approaches were significant. Participants in the intervention group were 31% less likely to develop type 2 diabetes than those in the comparison group.
I also lost weight and reduced abdominal fat more effectively. On average, the intervention group lost 3.3 kg in weight and 3.6 cm in waist circumference. The control group lost only 0.6 kg and waist size by 0.3 cm.
In the real world, researchers estimate that the program prevented about three cases of type 2 diabetes for every 100 participants. If widely applied to people at high risk for a disease that affects hundreds of millions of people around the world, this type of prevention could quickly become effective.
“This is the first robust clinical outcome in which we show, using the strongest available evidence, that a Mediterranean diet with calorie reduction, physical activity, and weight loss is a highly effective preventive measure against diabetes,” said Miguel Ángel Martínez González, professor of preventive medicine and public health at the University of Navarra and adjunct professor of nutrition at Harvard University, and one of the principal investigators of the project. “These small, sustained lifestyle changes, applied at scale to at-risk populations, could prevent thousands of new diagnoses each year. We hope to soon see similar evidence for other major public health challenges.”
Why this matters for the global health crisis
Type 2 diabetes is one of the fastest growing chronic diseases in the world. The International Diabetes Federation estimates that more than 530 million people worldwide currently live with diabetes. This increase is being accelerated by urbanization, less healthy eating, sedentary lifestyles, less physical activity, an aging population, and increasing rates of overweight and obesity.
Approximately 4.7 million adults in Spain have diabetes (mostly type 2), making it one of the countries with the highest prevalence in Europe. Across Europe, more than 65 million people have diabetes. Approximately 38.5 million people are affected in the United States, making it one of the countries with the highest per-patient medical costs in the world. Experts warn that type 2 diabetes increases the risk of cardiovascular, renal and metabolic complications, so prevention is essential.
“The Mediterranean diet works synergistically to improve insulin sensitivity and reduce inflammation. With PREDIMED-Plus, we demonstrate that combining calorie management with physical activity further enhances these benefits,” explained Miguel Ruiz Canela, professor and head of the Department of Preventive Medicine and Public Health at the Faculty of Medicine of the University of Navarra and lead author of the study. “This is a delicious, sustainable and culturally acceptable approach that provides a practical and effective way to prevent type 2 diabetes, a largely avoidable global disease.”
New research adds more context
Since the PREDIMED-Plus diabetes findings were produced, related research has continued to strengthen the broader picture. The PREDIMED-Plus body composition analysis published in JAMA Network Open found that a low-energy Mediterranean diet and physical activity help reduce total and visceral fat while slowing age-related loss of lean body mass in older adults who are overweight, obese, or have metabolic syndrome. This is important because loss of visceral fat and muscle is closely associated with cardiometabolic risk.
A recent PREDIMED-Plus study also looked at how sedentary time affects cardiovascular health. A 2026 study published in BMC Cardiovascular Disorders reported that replacing sedentary time with physical activity was associated with favorable 5-year changes in high-sensitivity troponin T, a blood marker associated with cardiac stress, but the pattern was not consistent across all atrial fibrillation-related biomarkers.
Other recent Mediterranean diet studies continue to support this pattern’s broader cardiovascular benefits. A 2025 review in Cardiovascular Research states that the Mediterranean diet is one of the most well-studied dietary patterns for cardiovascular prevention, citing large randomized trials such as PREDIMED, PREDIMED-Plus, CORDIOPREV, and the Lyon Diet Heart Study.
The 2026 analysis from the original PREDIMED trial also highlighted the potential importance of food quality in the diet. Participants with higher cumulative intakes of extra virgin olive oil had a lower risk of a wide range of cardiovascular diseases, but the association with regular olive oil was weaker. This finding supports a practical message for readers. The Mediterranean diet is more than just eating less and eating more plants. The type and quality of fat may also be important.
Practical strategies, not trends
Annual report of internal medicine The study was published with an editorial by Sharon J. Herring and Gina L. Tripicchio, nutrition and public health experts at Temple University in Philadelphia. They praised the clinical importance of this intervention and its potential as a model for type 2 diabetes prevention.
At the same time, he warned that bringing the same strategy to other parts of the world, including the United States, would require more than individual will. Barriers such as unequal access to healthy foods, urban environments that make physical activity difficult, and limited access to professional guidance can all get in the way. They argued that public policy should help create a healthier and more just environment.
This is especially important at a time when drugs to treat obesity and diabetes continue to attract significant attention. PREDIMED-Plus shows that drug therapy is not the only path to power. Ongoing lifestyle changes can lead to significant health gains if supported properly.
Built on decades of Mediterranean diet research
The PREDIMED-Plus project (2013-2024), which includes a diverse patient population, builds on the earlier PREDIMED study (2003-2010). A previous study showed that a Mediterranean diet rich in extra virgin olive oil and nuts reduced the risk of cardiovascular disease by 30%.
Researchers say the updated PREDIMED-Plus strategy could be used by primary care providers as a sustainable and cost-effective way to help prevent widespread type 2 diabetes. This intervention does not rely on extreme dieting. It combines familiar foods, moderate exercise, gradual weight loss, and professional support.
National research activities
The PREDIMED-Plus trial attracted a large network of researchers from all over Spain. Participating institutions include, in order of number of participants, the University of Navarra and the Health Service of Navarra (2 centres), the Barcelona Hospital (2 centres), the University of Valencia, the University of Rovira y Virgili (Reus), the IMIM Hospital, the Miguel Hernández University (Alicante), the Son Espace Hospital (Palma de Mallorca), the University of Málaga and the Reina Sofia Hospital. (Cordoba) and the University of Granada.
Other participants included Bioalaba and UPV/EHU (Vitoria), the University of the Balearic Islands, the Virgen de la Victoria Hospital (Málaga), the University of Las Palmas de Gran Canaria, the University of Leon, the Seville Primary Health Area, the Jiménez Díaz Foundation (Madrid), the Verín Hospital, the Carlos Hospital (Madrid), and the Carlos Hospital. (Madrid). University of Jaén, IMDEA Food Research Institute (Madrid).
The project also included international collaboration with Harvard University’s TH Chan School of Public Health. Most of the participating researchers are affiliated with CIBEROBN, CIBERESP, or CIBERDEM.
