Krebs 2012.

Study characteristics
Methods	Review comparison(s) addressed by this study: 3 Study design: RCT, parallel, multi‐centre (3) Trial registry number: ACTRN12606000490572 Total number of trial arms: 2 Year trial started: 2007 Sample size calculation: Yes Outcome(s) used for sample size calculation: Difference in weight and waist circumference Duration of run‐in period (weeks): NA What was the duration of the weight loss phase: 24 months What was the duration of the weight maintenance phase: NA Other notes about methods: NA
Participants	Country and setting: New Zealand, outpatient clinical centres in Wellington, Auckland and Christchurch Eligibility criteria: Participants with type 2 diabetes, according to WHO criteria, aged between 30 and 76 years with a BMI of ≥ 27 kg/m2. Participants were excluded if they were currently taking weight‐reducing medication; had lost > 5% weight in the past three months; had a psychiatric or eating disorder, HbA1c above 9.5% (80 mmol/mol); or suffered from renal disease (defined as glomerular filtration rate < 60 mL/min or urine albumin:creatinine ratio above 30 mg/mmol), abnormal liver enzymes, heart failure. active malignancies or myocardial infarction in the six months prior. Type 2 diabetes at baseline: Yes Impaired glucose tolerance at baseline: No Cardiovascular conditions/risk factors/events at baseline: No Gender: Mixed Total number randomised: 419 Total attrition in trial: 141 Treatment diet Participants randomised: 207 Participants withdrawn (voluntary): 48 Total attrition: 71 Control diet: Participants randomised: 212 Participants withdrawn (voluntary): 50 Total attrition: 70 Baseline data treatment diet: Randomised participants not included: None Age (years): mean (SD) 57.7 (9.9) Gender distribution (as reported): female 112/207 (54%), male 95/207 (46%) Weight (kg): mean (SD) 103.4 (19.7) BMI (kg/m2): mean (SD) 36.6 (6.7) DBP (mmHg): mean (SD) 76.8 (10.3) SBP (mmHg): mean (SD) 131.1 (14.8) HbA1c (%): mean (SD) 8.1 (1.2) LDL (mmol/L): mean (SD) 2.74 (0.91) HDL (mmol/L): mean (SD) 1.09 (0.32) Non‐HDL (mmol/L): NR TC (mmol/L): mean (SD) 4.77 (0.98) TG (mmol/L): median (IQR) 1.74 (1.32 to 2.29) Baseline data control diet: Randomised participants not included: None Age (years): mean (SD) 58.0 (9.2) Gender distribution (as reported): female 139/212 (66%), male 73/212 (34%) Weight (kg): mean (SD) 101.9 (20.1) BMI (kg/m2): mean (SD) 36.7 (6.4) DBP (mmHg): mean (SD) 76.6 (11.0) SBP (mmHg): mean (SD) 130.6 (17.0) HbA1c (%): mean (SD) 8.0 (1.2) LDL (mmol/L): mean (SD) 2.67 (0.92) HDL (mmol/L): mean (SD) 1.11 (0.28) Non‐HDL (mmol/L): NR TC (mmol/L): mean (SD) 4.61 (1.03) TG (mmol/L): median (IQR) 1.61 (1.18 to 2.33) Group differences at baseline: NR Characteristic(s) with significant group difference and relevant statistic: NA Other notes about participants: NA
Interventions	Energy (E) comparison of treatment vs control diets: Similar energy prescription/approach to restrict energy intake in both diets Treatment diet: Name (as reported) and brief description: Low‐fat high‐protein diet. Prescribed 30% of energy as protein, 40% as carbohydrate and 30% as fat. Energy prescription to reduce total energy intake by 2000 kJ/day using an individualised dietary prescription based on estimation of energy requirements Treatment diet type (carbohydrate‐fat‐protein): Low‐balanced‐high Exercise component? No Recipients: Subjects were 54% female, aged mean (SD) 57.7 (9.9), BMI mean (SD) 36.6 (6.7). 61.8% on lipid‐lowering drugs, 77.3% on BP‐lowering drugs and years on average with the diagnosis of diabetes of over 7 years. Why? Substituting protein for carbohydrate while maintaining reduced total fat may have particular benefits in type 2 diabetes. High‐protein diets promote weight loss, maintain lean body mass and improve lipid and glycaemic profiles in obese non‐diabetic individuals. Studies specifically in type 2 diabetes are limited, are generally short, often using very intensive interventions and/or providing a significant proportion of participants’ food, making the translation of the findings to a general population difficult. Therefore the specific long‐term effect of increasing protein intake in individuals with type 2 diabetes in a free‐living situation, using an intervention that can be realistically implemented, requires further investigation. What (materials)? Portion charts, sample diet plans and culturally appropriate recipes were made available for specific ethnic groups. What (procedures)? low‐fat high‐protein (30% of energy as protein, 40% as carbohydrate, 30% as fat). Group sessions every 2 weeks with an education component and time for discussing and concluded with goal‐setting. Dietary counselling included information on appropriate intakes and physical activity advice. Who provided? Dietitian How and where? Face‐to‐face, individual and group sessions When and how much? At the beginning of the study, individualised dietary prescription based on estimation of energy requirements were discussed on a one‐to‐one basis with each participant. Participants mainly had group sessions thereafter which were 1 hour long consisting of diet‐specific information and education and were conducted every 2 weeks for the first 6 months, then every month for the second 6 months. No further dietary advice was offered by the dietitians after 12 months. Participants were then asked to continue following their prescribed diets on their own in the second year. Outcome measures were assessed at 6, 12 and 24 months. Strategies to improve or maintain fidelity; tailoring and modification: The programmes were specifically designed for delivery in a ‘real‐world’ setting, keeping the time commitment for both participants and staff to levels that could be readily achieved in most healthcare systems. Ongoing self‐recording of food intake. Weekly text or email reminders and motivational messages were also offered to participants to enhance adherence to the diets. Extent of intervention fidelity: NR Concomitant interventions: Hypoglycemics, lipid‐lowering and antihypertensives Control diet: Name (as reported) and brief description: Low‐fat high‐carbohydrate diet. Prescribed 15% of energy as protein, 55% as carbohydrate and 30% as fat. Energy prescription to reduce total energy intake by 2000 kJ/day using an individualised dietary prescription based on estimation of energy requirements Control diet type (carbohydrate‐fat‐protein): Balanced‐balanced‐balanced Exercise component? No Recipients: Subjects were 66% female, aged mean (SD) 58.0 (9.2), BMI mean (SD) 36.7 (6.4). 69.3% on lipid‐lowering drugs, 74.5% on BP‐lowering drugs and on average with the diagnosis of diabetes of over 7 years. Why? NR What (materials)? Portion charts, sample diet plans and culturally appropriate recipes were made available for specific ethnic groups. What (procedures)? a low‐fat high‐carbohydrate (15% of energy as protein, 55% as carbohydrate, 30% as fat) diet. Group sessions every 2 weeks with an education component and time for discussing and concluded with goal‐setting. Dietary counselling included information on appropriate intakes and physical activity advice. Who provided? Dietitians How and where? Face‐to‐face, individual and group sessions When and how much? At the beginning of the study, individualised dietary prescription based on estimation of energy requirements were discussed on a one‐to‐one basis with each participant. Participants mainly had group sessions thereafter which were 1 hour long consisting of diet‐specific information and education and were conducted every 2 weeks for the first 6 months, then every month for the second 6 months. No further dietary advice was offered by the dietitians after 12 months. Participants were then asked to continue following their prescribed diets on their own in the second year. Outcome measures were assessed at 6, 12 and 24 months. Strategies to improve or maintain fidelity; tailoring and modification: The programmes were specifically designed for delivery in a ‘real‐world’ setting, keeping the time commitment for both participants and staff to levels that could be readily achieved in most healthcare systems. Ongoing self‐recording of food intake. Weekly text or email reminders and motivational messages were also offered to participants to enhance adherence to the diets. Extent of intervention fidelity: NR Concomitant interventions: Hypoglycemics, lipid‐lowering and antihypertensives
Outcomes	Change in body weight (kg) at 3 to < 12 months: Yes Change in body weight (kg) at ≥ 12 months: Yes Number of participants with 5% weight loss from baseline at 3 to < 12 months: No Number of participants with 5% weight loss from baseline at ≥ 12 months: No Change in BMI (kg/m2) at 3 to 12 months: No Change in BMI (kg/m2) at ≥ 12 months: No Number of participants with 5% BMI reduction from baseline at 3 to 12 months: No Number of participants with 5% BMI reduction from baseline at ≥ 12 months: No Change in DBP (mmHg) at ≥ 12 months: Yes Change in SBP (mmHg) at ≥ 12 months: Yes All‐cause mortality at ≥ 12 months: No Cardiovascular mortality at ≥ 12 months: No Non‐fatal myocardial infarction at ≥ 12 months: No Non‐fatal stroke at ≥ 12 months: No Diagnosis of type 2 diabetes mellitus at ≥ 12 months: No Change in HbA1c (%) at ≥ 12 months: Yes Change in LDL (mmol/L) at ≥ 12 months: Yes Change in HDL (mmol/L) at ≥ 12 months: Yes Change in non‐HDL (mmom/L) at ≥ 12 months: No Change in total cholesterol (TC) (mmol/L) at ≥ 12 months: Yes Change in triglycerides (or triacylglycerides) (TG) (mmol/L) at ≥ 12 months: Yes Participant‐reported adverse effects: No
Notes	Number and type of records(s): journal article Trial acronym/name: DEWL Trial funded by: Health Research Council of New Zealand (grant 06/337) Declaration of interest: "The authors declare that there is no duality of interest associated with this manuscript."