• Posted August 26, 2025

Mediterranean Diet Can Protect Against Type 2 Diabetes

A Mediterranean-style diet can significantly decrease risk of type 2 diabetes in people who are overweight or obese, a new study says.

People had 31% lower odds of diabetes if they adhered to a Mediterranean diet, cut their calories and exercised regularly, researchers reported Aug. 25 in the Annals of Internal Medicine.

“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,” co-researcher Dr. Frank Hu said in a news release. He’s chair of nutrition at Harvard T.H. Chan School of Public Health in Boston.

In a Mediterranean-style diet, people eat lots of fruits, vegetables, whole grains and healthy fats like olive oil. They moderate their amount of dairy and lean proteins like fish and chicken, and eat little to no red meat.

For this study, researchers analyzed data on more than 4,700 people 55 to 75 participating in a large-scale nutrition and lifestyle study in Europe. The participants all were overweight or obese, but had not developed type 2 diabetes.

Half were asked to follow a Mediterranean diet, cut calories by about 600 per day and engage in moderate physical activity like walking, strength training and balance exercises. The other half received some advice regarding the Mediterranean diet, but weren’t asked to cut calories.

Results showed a lower diabetes risk for those on the Mediterranean diet, with a greater effect found in men than women.

People in the Mediterranean diet group also lost around seven pounds on average and reduced their waistline by nearly one and a half inches, after about six years of follow-up.

“In practical terms, adding calorie control and physical activity to the Mediterranean diet prevented around 3 out of every 100 people from developing diabetes — a clear, measurable benefit for public health,” researcher Miguel Martínez-González, an adjunct professor of nutrition at Harvard, said in a news release.

More information

The Mayo Clinic has more on the Mediterranean diet.

SOURCE: Harvard T.H. Chan School of Public Health, news release, Aug. 25, 2025