Mediterranean diet trumps low-fat diet for patients with diabetes

A Mediterranean diet rich in nuts, fruits and vegetables delayed the need for antihyperglycemic therapy in overweight patients with type 2 diabetes more than a low-fat diet.

After four years, 44% of adults randomly assigned to a Mediterranean-style diet required treatment compared with 70% of adults assigned to a low-fat diet (HR=63; 95% CI, 0.51-0.86).

Researchers in Italy compared the effects of the two diets on the need for antihypertensive therapy in 215 obese or overweight adults with newly diagnosed type 2 diabetes. Participants were not previously treated with antihypertensive drugs and had HbA1c levels <11%.

Participants assigned to the Mediterranean-style diet (n=108) ate more fish, vegetables, nuts, whole grains and olive oil. Less than 50% of daily calories came from carbohydrates and no less than 30% of daily calories from fat. The low-fat diet (n=107), on the other hand, was rich in whole grains and restricted fats and sweets. Participants were restricted to no more than 30% of daily calories from fat and 10% of daily calories from saturated fat. Daily calorie restrictions were 1,800 for men and 1,500 for women.

All participants met with nutritionists and dietitians during monthly sessions for the first year, and every other month through year four of the study. Researchers used data gathered during these sessions and food diaries to assess adherence to the diets.

The benefits of a Mediterranean diet were observed early in the study. The absolute difference in weight loss between the two groups was –4.4 lb at one year. At 18 months, 12% of the Mediterranean diet group needed antihyperglycemic medication vs. 24% of the low-fat diet group.

Throughout the study, participants assigned to the Mediterranean diet also experienced and maintained greater improvements in coronary risk measures, including increased HDL and decreased triglycerides.

Esposito K. Ann Intern Med. 2009;151:306-314.