A new study led by Harvard T.H. Chan School of Public Health and Spanish researchers has shown that combining a Mediterranean-style diet with calorie reduction, exercise, and professional support can reduce the risk of type 2 diabetes (T2D) by 31%.
Published on August 25, 2025, in the Annals of Internal Medicine, the study offers strong evidence that sustainable lifestyle changes could prevent millions of diabetes cases globally.
Study found participants who followed a Mediterranean diet and reduced calorie intake by about 600 calories per day, while engaging in regular physical activity and receiving support, had a 31% lower risk of developing T2D.
The intervention group lost an average of 3.3 kg and trimmed their waist by 3.6 cm, compared to 0.6 kg and 0.3 cm in the control group.
Simply following a Mediterranean diet without calorie limits or exercise did not yield the same benefits.
The Mediterranean diet has already been linked to many health benefits, including better heart health, lower inflammation, and improved insulin sensitivity. But this study highlights that adding modest lifestyle changes makes a significant difference in diabetes prevention.
“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,” said Frank Hu, senior co-author and chair of the Department of Nutrition at Harvard.
Professor Miguel Martínez-González added, “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.”
The study is published in Annals of Internal Medicine.
Copyright © 2025 Knowridge Science Report. All rights reserved.
