Clinical Efficacy of Two Hypocaloric Diets That Vary in Overweight Patients With Type 2 Diabetes: Comparison of moderate fat versus carbohydrate reductions

Approximately 80% of patients with type 2 diabetes are overweight/obese (1), and weight loss is the mainstay of treatment for these individuals. However, there is growing controversy as to whether reduced-fat or reduced-carbohydrate diets are best suited for this purpose, and results (2–8) in nondiabetic subjects suggest that lower carbohydrate diets are similarly or more efficacious in improving weight, triglycerides, and HDL cholesterol. There are no published randomized studies evaluating the role of dietary macronutrients with respect to weight loss and cardiovascular risk improvement in patients with type 2 diabetes. Thus, we randomized diet-treated patients with type 2 diabetes to hypocaloric diets, moderately restricted in either carbohydrate or fat, to determine whether weight loss or metabolic improvement differed as a function of macronutrient composition. A total of 29 patients with diet-treated type 2 diabetes were recruited from the San Francisco Bay area. All subjects gave written informed consent. Inclusion criteria included BMI 27–36 kg/m2, fasting plasma glucose concentration 7.2–8.3 mmol/l, no use of antihyperglycemic medications, and stable weight for 3 months. Subjects on anti-hypertensive or cholesterol-lowering drugs or aspirin were allowed to continue their medications. Insulin-mediated glucose uptake was quantified by a modification (9) of the insulin suppression test as originally described (10) and validated (11). In this test, a 180-min infusion of somatostatin (0.27 μg/m2 per min), insulin (25 mU/m2 per min), …