In the short-term, among patients with type 2 diabetes, low-to-moderate carbohydrate diets have a greater glucose-lowering effect than do high-carbohydrate diets. However, compared with usual diet, the effect of a behavioral intervention promoting a low-carbohydrate/high-unsaturated fat and high-protein dietary pattern among individuals with prediabetes or untreated type 2 diabetes is not well understood.~The overall goal of this randomized controlled trial is to study the effect of a behavioral intervention promoting a low-carbohydrate/high-unsaturated fat and high-protein dietary pattern compared with usual diet on hemoglobin A1c (HbA1c) and other metabolic risk factors among individuals with or at high risk of diabetes (HbA1c 6.0-6.9%).~A total of 150 participants with HbA1c 6.0-6.9% will be recruited and randomly assigned to either a 6-month behavioral modification program designed to reduce carbohydrate intake (initial target <40 g digestible carbohydrates, final target <60 g digestible carbohydrates) or to usual diet in a 1:1 randomization ratio.~The primary outcome will be the difference between the active intervention and control groups for change in HbA1c from baseline to 6 months. Secondary outcomes will be fasting glucose, systolic blood pressure, total-to-high-density lipoprotein-cholesterol ratio, and body weight.~Findings from this study may provide evidence about the role of carbohydrate restriction in individuals with or at high risk of type 2 diabetes.
The proposed randomized controlled trial will test the effect of a low-carbohydrate diet on hemoglobin A1c among individuals with elevated hemoglobin A1c that are within the range of prediabetes or diabetes. Results may provide evidence about the role of carbohydrate restriction in individuals with or at high risk of type 2 diabetes.