None listed
Conditions
Brief summary
Reducing the incidence and impact of obesity and diabetes is a priority. Diet and lifestyle modification remains the cornerstone of management. Despite the widespread promotion of low-fat/high-carbohydrate (LFHC) diets, rates of obesity continue to climb. Short-term studies in non-diabetic subjects suggest high-protein/low-carbohydrate (HPLC) diets may facilitate greater weight-loss. This randomised controlled trial will assess the impact of a HPLC diet compared with a LFHC diet in 450 overweight individuals with type 2 diabetes. Subjects will receive group-based and individualized dietitian support. Weight, diabetes control, cardiovascular disease risk, adverse effects and cost-effectiveness will be assessed over 24 months. Demonstration that a HPLC diet is effective and cost-effective without significant adverse effects in subjects with diabetes would have a wide-ranging impact for individual and public health advice both in New Zealand and internationally.
Interventions
High protein diet versus a low fat diet:
Group 2 (Intervention) “High-Protein:Reduced-Carbohydrate”: Reduced carbohydrate (40% total energy) with a focus on whole grains, low glycaemic index foods, and high fibre (30g/day). The diet will also include increased protein (30% total energy) and moderate fat (30% total energy) with a focus on Monounsaturated Fatty Acids and Polyunsaturated Fatty Acids and no more than 10% being saturated fat, aiming for a reduction in total energy intake of 500kcal
High protein diet versus a low fat diet: Group 2 (Intervention) “High-Protein:Reduced-Carbohydrate”: Reduced carbohydrate (40% total energy) with a focus on whole grains, low glycaemic index foods, and high fibre (30g/day). The diet will also include increased protein (30% total energy) and moderate fat (30% total energy) with a focus on Monounsaturated Fatty Acids and Polyunsaturated Fatty Acids and no more than 10% being saturated fat, aiming for a reduction in total energy intake of 500kcal/day. All subjects will take part in a 12-month group-based programme, attending fortnightly meetings with a dietitian for the first six months to facilitate weight loss and adherence to the specific dietary protocol. This will be followed by a less intensive 6-month period with monthly sessions. Subjects will then be asked to maintain their weight loss by adhering to the dietary protocol, but will have no further dietitian input for a further 12 months, apart from monthly weighs.
Sponsors
New Zealand Health Research Council
Study design
Allocation
Randomised controlled trial
Intervention model
Parallel
Primary purpose
Treatment
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
30 Years to 75 Years
Healthy volunteers
No
Inclusion criteria
Overweight (BMI equal or greater than 27kg/m2) adults with established type 2 diabetes requiring oral antidiabetic agents and/or insulin, or are diet-controlled and meet the WHO criteria for diabetes.
Exclusion criteria
Current or recent weight change (>3kg) in the previous three months, on weight-reducing medication (e.g. Orlistat or Sibutrimine), pregnancy or lactation, planning pregnancy during the timeframe of the study, an eating disorder or active psychiatric illness, serum HbA1c>9.5, diabetic nephropathy or other chronic renal failure, abnormal liver enzymes (Aspartate aminotranferase (AST), Alanine transferase (ALT) and Gamma-glutamyl transpeptidase (GGT) >3 x upper limit of normal), active gallbladder disease, heart failure (New York Heart Association class III or IV), myocardial infarction in the last six months, known malignancy within the last 5 years and not in remission, ongoing oral steroid use, or other reasons why taking part would be practically difficult (e.g. institutional care).
Outcome results
None listed