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

Diabetologia. 2012 Apr;55(4):905-14. doi: 10.1007/s00125-012-2461-0.


Aims/hypothesis: 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. Study design Multicentre parallel (1:1) design, blinded randomised controlled trial.

Methods: 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.

Results: A total of 419 participants were enrolled (mean±SDage 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.

Conclusions/interpretation: 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

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Blood Pressure / physiology
  • Body Weight / physiology
  • Diabetes Mellitus, Type 2 / diet therapy*
  • Diabetes Mellitus, Type 2 / physiopathology
  • Diet, Reducing*
  • Dietary Carbohydrates*
  • Dietary Proteins*
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Middle Aged
  • Treatment Outcome
  • Weight Loss / physiology*


  • Dietary Carbohydrates
  • Dietary Proteins