Background: Low-carbohydrate and low-fat calorie-restricted diets are recommended for weight loss in overweight and obese people with type 2 diabetes.
Objective: To compare the effects of a low-carbohydrate Mediterranean-style or a low-fat diet on the need for antihyperglycemic drug therapy in patients with newly diagnosed type 2 diabetes.
Design: Single-center, randomized trial. Randomization was computer-generated and unstratified. Allocation was concealed in sealed study folders held in a central, secure location until participants gave informed consent. Participants and investigators were aware of treatment assignment, and assessors of the primary outcome were blinded.
Setting: Teaching hospital in Naples, Italy.
Patients: 215 overweight people with newly diagnosed type 2 diabetes who were never treated with antihyperglycemic drugs and had hemoglobin A1c (HbA1c) levels less than 11%.
Intervention: Mediterranean-style diet (<50% of daily calories from carbohydrates) (nÂ = 108) or a low-fat diet (<30% of daily calories from fat) (nÂ = 107).
Measurements: Start of antihyperglycemic drug therapy, defined by protocol as indicated for follow-up HbA1c level greater than 7% (primary outcome), and changes in weight, glycemic control, and coronary risk factors (secondary outcomes).
Results: After 4 years, 44% of patients in the Mediterranean-style diet group and 70% in the low-fat diet group required treatment (absolute difference, âˆ’26.0 percentage points [95% CI, âˆ’31.1 to âˆ’20.1 percentage points]; hazard ratio, 0.63 [CI, 0.51 to 0.86]; hazard ratio adjusted for weight change, 0.70 [CI, 0.59 to 0.90]; PÂ < 0.001). Participants assigned to the Mediterranean-style diet lost more weight and experienced greater improvements in some glycemic control and coronary risk measures than did those assigned to the low-fat diet.
Limitations: Investigators responsible for initiating drug therapy were not blinded to treatment assignment. Dietary intake was self-reported.
Conclusion: Compared with a low-fat diet, a low-carbohydrate, Mediterranean-style diet led to more favorable changes in glycemic control and coronary risk factors and delayed the need for antihyperglycemic drug therapy in overweight patients with newly diagnosed type 2 diabetes.
Primary Funding Source: Second University of Naples.