Low-Carbohydrate Dietary Pattern on Glycemic Outcomes Trial
Condition: Diabetes; PreDiabetes; Metabolic Disease; Hyperglycemia; Diet Modification; Glucose Intolerance; Glucose Metabolism Disorders (Including Diabetes Mellitus); Endocrine System Diseases
MeSH terms: Diabetes Mellitus; Hyperglycemia; Prediabetic State; Glucose Intolerance; Metabolic Diseases; Glucose Metabolism Disorders; Endocrine System Diseases
Study type: Interventional

Summary: 
      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.
    

Detailed description: 
      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.
    

Intervention name(s): Low-Carbohydrate Diet
Intervention type(s): Behavioral
Intervention description(s): Behavioral modification to reduce carbohydrate consumption. Target <40 g net carbohydrates per day for first 3 months; <60 g net carbohydrates per day for months 4 onwards. The intervention will consist of 4 weekly individual counseling sessions, followed by 4 group sessions held every other week, with phone follow-ups in between group sessions. For the last 3 months of the study, there will be 3 monthly group sessions and 3 telephone follow-ups.
At baseline, participants will receive written information with standard physical activity recommendations.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Investigator, Outcomes Assessor)
Primary purpose: Prevention
Keywords: Prediabetes; Diabetes; Low-Carbohydrate Diet