Wycherley 2012.

Study characteristics
Methods	Review comparison(s) addressed by this study: 1 Study design: RCT, parallel, single‐centre (1) Trial registry number: ACTRN12606000002583 Total number of trial arms: 2 Year trial started: 2005 Sample size calculation: Yes Outcome(s) used for sample size calculation: Change in weight, change in fat mass (FM), change in fat‐free mass (FFM). Duration of run‐in period (weeks): NA What was the duration of the weight loss phase: 52 weeks What was the duration of the weight maintenance phase: NA Other notes about methods: NA
Participants	Country and setting: Australia, outpatient research clinic in Adelaide. Key foods specific to each prescribed dietary pattern (accounting for approximately 60% of energy) were provided on a fortnightly basis until week 12. Eligibility criteria: Participants were overweight and obese males. Participants were excluded if they had BMI < 27 or > 40 kg/m2; were aged < 20 or > 65 years; had diabetes or uncontrolled hypertension, a history of renal, hepatic, coronary, gastrointestinal or metabolic disease or malignancy; were taking medication which might affect insulin sensitivity or hypoglycaemic drugs or were smokers. Type 2 diabetes at baseline: No Impaired glucose tolerance at baseline: Unclear Cardiovascular conditions/risk factors/events at baseline: No Gender: Male Total number randomised: 123 Total attrition in trial: 55 Treatment diet Participants randomised: 59 Participants withdrawn (voluntary): 5 Total attrition: 26 Control diet: Participants randomised: 64 Participants withdrawn (voluntary): 4 Total attrition: 29 Baseline data treatment diet: Randomised participants not included: 2/59 Age (years): mean (SE) 50.1 (1.2) Gender distribution (as reported): female 0%, male 100% Weight (kg): mean (SE) 105.2 (1.9) BMI (kg/m2): mean (SE) 33.8 (0.6) DBP (mmHg): mean (SE) 85.7 (1.4) SBP (mmHg): mean (SE) 134.5 (2.0) HbA1c (%): NR LDL (mmol/L): mean (SE) 3.2 (0.1) HDL (mmol/L): mean (SE) 1.2 (0.05) Non‐HDL (mmol/L): NR TC (mmol/L): mean (SE) 5.2 (0.13) TG (mmol/L): mean (SE) 1.7 (0.12) Baseline data control diet: Randomised participants not included: 3/64 Age (years): mean (SE) 49.2 (1.2) Gender distribution (as reported): female 0%, male 100% Weight (kg): mean (SE) 102.6 (1.8) BMI (kg/m2): mean (SE) 32.7 (0.5) DBP (mmHg): mean (SE) 84.2 (1.3) SBP (mmHg): mean (SE) 135.9 (1.6) HbA1c (%): NR LDL (mmol/L): mean (SE) 3.2 (0.1) HDL (mmol/L): mean (SE) 1.3 (0.05) Non‐HDL (mmol/L): NR TC (mmol/L): mean (SE) 5.3 (0.1) TG (mmol/L): mean (SE) 1.9 (0.1) Group differences at baseline: No 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: High protein (HP) diet. Macronutrient profile of 35% protein, 40% carbohydrate and 25% fat (total 53 g, saturated 14 g). Energy prescription of 7000 kJ per day Treatment diet type (carbohydrate‐fat‐protein): Low‐balanced‐high Exercise component? No Recipients: Men only N = 57, mean (SE) age 50.1(1.2) years, mean (SE) weight 105.2 (1.9) kg, mean (SE) 33.8 (0.6) kg/m2 Why? Sex differences in protein kinetics have been previously documented; hence, whether comparable effects of HP diet previously observed in females are also experienced by males remains largely unknown. This requires urgent investigation as males have a higher proportion of visceral adipose tissue, and a greater risk of cardiometabolic diseases. What (materials)? "Participants were supplied with a 2‐week provision of diet‐specific key foods, representing approximately 60% of the energy intake, to improve compliance and allow them to familiarize themselves with the food types and quantities utilized in the study. They were also supplied with digital weighing scales." What (procedures)? Participants were prescribed a HP diet made up of protein 35% (142 g, roughly 1.30 g per kg per day), carbohydrate 40% (135 g), fat 25% (total 53 g, saturated 14 g). Within the HP diet the prescribed daily protein distribution was approximately 20% (13 g) during the morning, 30% (39 g) at lunch time and 60% (78 g) of protein during the afternoon/evening period. Guided by dietitians every two weeks then monthly. Participants received detailed dietary prescription, meal planning advice and recipe information. To further facilitate dietary compliance, the dietary patterns were structured into quantities of daily foods and presented as a food checklist. Who provided? Dietitian How and where? Face‐to‐face session at the research centre When and how much? Dietary intervention for 52 weeks. At baseline, week 12 and at the end of the intervention (week 52), participants attended the clinic following an overnight fast for outcome assessment. Participants met individually with a qualified dietitian at baseline, and every 2 weeks during the first 12 weeks of the study and monthly thereafter. Strategies to improve or maintain fidelity; tailoring and modification: Participants were required to keep daily semi‐quantitative food records in which foods consumed with a variable weight were weighed using kitchen scales before recording and foods with a standard unit (i.e. slice of bread) were recorded without pre‐weighing. Dietary intake was assessed using a computerised database (Foodworks Professional Edition, version 4, 1998; Xyris Software, Highgate Hill, Australia) based on the analysis of 3 nonconsecutive days (1 weekend day and 2 weeks days) of each 2‐week period of diet‐record data throughout the study. The composite value for dietary intake for weeks 0–12 and 12–52 (Table 2) was calculated as an average of the 2 week diet‐record data blocks within each of the respective periods. To further facilitate dietary compliance, the dietary patterns were structured into quantities of daily foods and presented as a food checklist. Throughout weeks 0–12, participants were supplied with a 2‐week provision of diet‐specific key foods, representing approximately 60% of the energy intake, to improve compliance and allow them to familiarise themselves with the food types and quantities utilised in the study. Extent of intervention fidelity: On the basis of food record data, participants in both groups showed good compliance to the prescribed diets. The diets were similar in total energy (P > 0.05)but participants in the HP diet group consumed less carbohydrate, and more protein and fat than those consuming the HC diet. Concomitant interventions: Participants were excluded if they were taking hypoglycaemic medication or drugs which affect insulin sensitivity. Control diet: Name (as reported) and brief description: High‐carbohydrate (HC) diet. Macronutrient profile of 17% protein, 58% carbohydrate and 25% fat (total 51 g, saturated 14 g). Energy prescription of 7000 kJ per day Control diet type (carbohydrate‐fat‐protein): Balanced‐balanced‐balanced Exercise component? No Recipients: Men only N = 61, mean (SE) age 49.2 (1.2) years, mean (SE) weight 102.6 (1.8) kg, mean (SE) 32.7 (0.5) kg/m2 Why? NR What (materials)? "Participants were supplied with a 2‐week provision of diet‐specific key foods, representing approximately 60% of the energy intake, to improve compliance and allow them to familiarize themselves with the food types and quantities utilized in the study. They were also supplied with digital weighing scales." What (procedures)? Participants were prescribed a HC diet made up of protein 17% (88 g, roughly 0.85 g per kg per day), carbohydrate 58% (198 g), fat 25% (total 51 g, saturated 14 g) that was designed to reflect current conventional dietary recommendations. Guided by dietitians every two weeks then monthly Who provided? Dietitian How and where? Face‐to‐face session at the research centre When and how much? Dietary intervention for 52 weeks. At baseline, week 12 and at the end of the intervention (week 52), participants attended the clinic following an overnight fast for outcome assessment. Participants met individually with a qualified dietitian at baseline, and every 2 weeks during the first 12 weeks of the study and monthly thereafter. Strategies to improve or maintain fidelity; tailoring and modification: Participants were required to keep daily semi‐quantitative food records in which foods consumed with a variable weight were weighed using kitchen scales before recording and foods with a standard unit (i.e. slice of bread) were recorded without pre‐weighing. Dietary intake was assessed using a computerised database (Foodworks Professional Edition, version 4, 1998; Xyris Software, Highgate Hill, Australia) based on the analysis of 3 nonconsecutive days (1 weekend day and 2 weeks days) of each 2‐week period of diet‐record data throughout the study. The composite value for dietary intake for weeks 0–12 and 12–52 (Table 2) was calculated as an average of the 2‐week diet‐record data blocks within each of the respective periods. To further facilitate dietary compliance, the dietary patterns were structured into quantities of daily foods and presented as a food checklist. Throughout weeks 0–12, participants were supplied with a 2‐week provision of diet‐specific key foods, representing approximately 60% of the energy intake, to improve compliance and allow them to familiarise themselves with the food types and quantities utilised in the study. Extent of intervention fidelity: On the basis of food record data, participants in both groups showed good compliance to the prescribed diets. The diets were similar in total energy (P > 0.05)but participants in the HP diet group consumed less carbohydrate, and more protein and fat than those consuming the HC diet. Concomitant interventions: Participants were excluded if they were taking hypoglycaemic medication or drugs which affect insulin sensitivity.
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: Yes 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: No 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: Yes
Notes	Number and type of records(s): journal article Trial acronym/name: None Trial funded by: Meat and Livestock Australia through a project grant Declaration of interest: "The authors declare no conflict of interest."