The Diabetes Excess Weight Loss (DEWL) Trial: a randomised controlled trial of high-protein versus high-carbohydrate diets over 2 years in type 2 diabetes
To compare the effectiveness of low-fat high-protein and low-fat high-carbohydrate dietary advice on weight loss, using group-based interventions, among overweight people with type 2 diabetes.
Multicentre parallel (1:1) design, blinded randomised controlled trial.
Individuals with type 2 diabetes aged 30–75 years and a BMI >27 kg/m2 were randomised, by an independent statistician using sequentially numbered sealed envelopes, to be prescribed either a low-fat high-protein (30% of energy as protein, 40% as carbohydrate, 30% as fat) or a low-fat high-carbohydrate (15% of energy as protein, 55% as carbohydrate, 30% as fat) diet. Participants attended 18 group sessions over 12 months. Primary outcomes were change in weight and waist circumference assessed at baseline, 6 and 12 months. Secondary outcomes were body fatness, glycaemic control, lipid profile, blood pressure and renal function. A further assessment was undertaken 12 months after the intervention. Research assessors remained blinded to group allocation throughout. Intention-to-treat analysis was performed.
A total of 419 participants were enrolled (mean ± SD age 58 ± 9.5 years, BMI 36.6 ± 6.5 kg/m2 and HbA1c 8.1 ± 1.2% (65 mmol/mol)). The study was completed by 70% (294/419). No differences between groups were found in change in weight or waist circumference during the intervention phase or the 12-month follow-up. Both groups had lost weight (2–3 kg, p < 0.001) and reduced their waist circumference (2–3 cm, p < 0.001) by 12 months and largely maintained this weight loss for the following 12 months. By 6 months, the difference in self-reported dietary protein between groups was small (1.1% total energy; p < 0.001). No significant differences between groups were found in secondary outcomes: body fatness, HbA1c, lipids, blood pressure and renal function. There were no important adverse effects.
In a ‘real-world’ setting, prescription of an energy-reduced low-fat diet, with either increased protein or carbohydrate, results in similar modest losses in weight and waist circumference over 2 years.
Australia New Zealand Clinical Trials Register ACTRN12606000490572
The Health Research Council of New Zealand (06/337).
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- The Diabetes Excess Weight Loss (DEWL) Trial: a randomised controlled trial of high-protein versus high-carbohydrate diets over 2 years in type 2 diabetes
Volume 55, Issue 4 , pp 905-914
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- Diabetes mellitus type 2
- Diet, carbohydrate-restricted
- Randomised controlled trial
- Weight loss
- Industry Sectors
- Author Affiliations
- 1. Department of Medicine, University of Otago, Wellington, New Zealand
- 6. Endocrine, Diabetes and Research Centre, Capital and Coast Health, Private Bag 7902, Wellington, New Zealand
- 2. School of Population Health, University of Auckland, Auckland, New Zealand
- 3. Department of Medicine, University of Otago, Christchurch, New Zealand
- 4. Auckland Diabetes Centre, Auckland District Health Board, Greenlane Clinical Centre, Auckland, New Zealand
- 5. Edgar National Centre for Diabetes and Obesity Research (ENCDOR), Department of Medicine, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand