Tay 2008.

Study characteristics
Methods	Review comparison(s) addressed by this study: 1 Study design: RCT, parallel, number of centres NR Trial registry number: ACTRN12606000203550 Total number of trial arms: 2 Year trial started: 2006 Sample size calculation: No Outcome(s) used for sample size calculation: NA 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: NR; likely Australia based on authors and funders Eligibility criteria: Participants aged 18 to 65 years with abdominal obesity and the presence of at least one additional risk factor for metabolic syndrome. Participants were excluded if they had a history of liver, cardiovascular, peripheral vascular, respiratory or gastrointestinal diseases; diabetes; or malignancy. Type 2 diabetes at baseline: No Impaired glucose tolerance at baseline: Mixed Cardiovascular conditions/risk factors/events at baseline: No Gender: Mixed Total number randomised: 118 Total attrition in trial: 30 Treatment diet Participants randomised: 57 Participants withdrawn (voluntary): 12 Total attrition: 12 Control diet: Participants randomised: 61 Participants withdrawn (voluntary): 18 Total attrition: 18 Baseline data treatment diet: Randomised participants not included: 12/57 Age (years): mean (SD) 50.3 (8.4) Gender distribution (as reported): female 31/45 (68.9%), male 14/45 (31.1%) Weight (kg): mean (SD) 94.4 (15.5) BMI (kg/m2): mean (SD) 33.9 (4.3) DBP (mmHg): mean (SD) 73.6 (11.6) SBP (mmHg): mean (SD) 133.5 (14.5) HbA1c (%): NR LDL (mmol/L): mean (SD) 3.2 (0.9) HDL (mmol/L): mean (SD) 1.4 (0.3) Non‐HDL (mmol/L): NR TC (mmol/L): mean (SD) 5.4 (0.9) TG (mmol/L): mean (SD) 1.6 (0.7) Baseline data control diet: Randomised participants not included: 18/61 Age (years): mean (SD) 51.0 (7.5) Gender distribution (as reported): female 26/43 n/N (60.5%), male 17/43 n/N (39.5%) Weight (kg): mean (SD) 95.2 (12.6) BMI (kg/m2): mean (SD) 33.5 (4.1) DBP (mmHg): mean (SD) 77.8 (10.1) SBP (mmHg): mean (SD) 136.1 (12.6) HbA1c (%): NR LDL (mmol/L): mean (SD) 3.3 (0.7) HDL (mmol/L): mean (SD) 1.3 (0.4) Non‐HDL (mmol/L): NR TC (mmol/L): mean (SD) 5.4 (0.8) TG (mmol/L): mean (SD) 1.8 (0.8) 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: Very‐low‐carbohydrate high‐fat (VLCHF) diet. 4% of total energy as carbohydrate, 35% protein and 61% total fat (20% saturated). Carbohydrate intake was restricted to < 20 g/day during the first 8 weeks of the study whereafter subjects were given the option to increase to < 40 g/day for the remaining 16 weeks. Moderate energy restriction of  30% (prescription of 6000 kJ for women and 7000 kJ for men). Treatment diet type (carbohydrate‐fat‐protein): Very low‐high‐high Exercise component? No Recipients: Abdominally obese participants, 68.9% female, aged 50.3 (8.4) with BMI 33.9 (4.3) and weight 94.4 (15.5) Why? VLCHF diet produces greater reductions in triacylglycerols (TAG) and increases in high‐density lipoprotein cholesterol (HDL‐C) and at least comparable changes in blood pressure and insulin resistance, without detrimental effects on low‐density lipoprotein cholesterol (LDL‐C) for periods up to 1 year. What (materials)? Key foods for the macronutrient profile, comprising approximately 30% of energy, was provided for the first eight weeks. Thereafter $40 food vouchers were given to participants for the next 16 weeks. Scales for weighing food were provided. What (procedures)? Subjects were instructed to follow a very‐low‐carbohydrate diet and were given key foods for eight weeks and food vouchers for the following 16 weeks to assist with compliance. Semiquantitative food records were kept and food was weighed. A qualified dietitian provided individualised dietary advice, meal planning, and recipe information at each clinic visit. Three‐day food records were kept every two weeks and dietary composition was determined. Dietary intake was assessed by food frequency questionnaire. Who provided? Qualified dietitians provided individual consultations. How and where? Face‐to‐face consultations with dieticians at a clinic and food records kept by participants at home When and how much? During the course of the 24‐week intervention subjects attended the clinic fortnightly for eight weeks and monthly thereafter. Key foods were provided on a fortnightly basis for eight weeks. Food vouchers were provided for the remaining 16 weeks on a monthly basis. Food records were completed daily and individual consultations with dietitians occurred during clinic visits. Three‐day food records were done every two weeks and food frequency questionnaires were completed at baseline and 24 weeks. Strategies to improve or maintain fidelity; tailoring and modification: Keeping of food records and analysis thereof for dietary composition, weighing of food, regular determination of body weight and plasma ketones as study outcome, regular meetings with dietitian, provision of key foods and food vouchers. Dietary advice was individualised. Subjects in the HCLF diet were asked to restrict saturated fat intake to < 10 g/day for the study duration. Extent of intervention fidelity: High level of dietary compliance found according to dietary data and the level of plasma ketones Concomitant interventions: In the total group, 17.0% were taking estrogen (12.5% HRT and 4.5% oral contraceptive), 30.7% were on antihypertensive medications, 20.5% were taking lipid‐lowering medication and none were taking hypoglycemic medication; no significant differences between medication use in the two trial arms. Control diet: Name (as reported) and brief description: High‐carbohydrate low‐fat (HCLF) diet. 46% of total energy as carbohydrate, 24% as protein and 30% as total fat (< 8% saturated). Moderate energy restriction of  30% (prescription of 6000 kJ for women and 7000 kJ for men) Control diet type (carbohydrate‐fat‐protein): Balanced‐balanced‐high Exercise component? No Recipients: Abdominally obese participants, 60.5% female, aged 51.0 (7.5) with BMI 33.5 (4.1) and weight 95.2 (12.6). Why? Dietary recommendations for the management of weight and treatment of obesity are to follow a high‐carbohydrate, low‐fat, energy‐restricted diet. What (materials)? Key foods for the macronutrient profile, comprising approximately 30% of energy, were provided for the first eight weeks. Thereafter $40 food vouchers were given to participants for the next 16 weeks. Scales for weighing food were provided. What (procedures)? Subjects were instructed to follow a high‐carbohydrate low‐fat diet and were given key foods for eight weeks and food vouchers for the following 16 weeks to assist with compliance. Semiquantitative food records were kept and food was weighed. Individual consultations with a dietitian comprised dietary advice and meal planning. Three‐day food records were kept every two weeks and dietary composition was determined. Dietary intake was assessed by food frequency questionnaire. Who provided? Qualified dietitians provided individual consultations. How and where? Face‐to‐face consultations with dieticians at a clinic and food records kept by participants at home When and how much? During the course of the 24‐week intervention subjects attended the clinic fortnightly for eight weeks and monthly thereafter. Key foods were provided on a fortnightly basis for eight weeks. Food vouchers were provided for the remaining 16 weeks on a monthly basis. Food records were completed daily and individual consultations with dietitians occurred during clinic visits. Three‐day food records were done every two weeks and food frequency questionnaires were completed at baseline and 24 weeks. Strategies to improve or maintain fidelity; tailoring and modification: Keeping of food records and analysis thereof for dietary composition, weighing of food, regular determination of body weight and plasma ketones as study outcome, regular meetings with dietitian, provision of key foods and food vouchers. Dietary advice was individualised. Subjects in the HCLF diet were asked to restrict saturated fat intake to < 10 g/day for the study duration. Extent of intervention fidelity: High level of dietary compliance found according to dietary data Concomitant interventions: In the total group, 17.0% were taking estrogen (12.5% HRT and 4.5% oral contraceptive), 30.7% were on antihypertensive medications, 20.5% were taking lipid‐lowering medication and none were taking hypoglycemic medication; no significant differences between medication use in the two trial arms
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: Yes Number of participants with 5% weight loss from baseline at ≥ 12 months: Yes Change in BMI (kg/m2) at 3 to 12 months: Yes Change in BMI (kg/m2) at ≥ 12 months: Yes 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 (mmol/L) at ≥ 12 months: Yes 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: National Heart Foundation of Australia and National Health and Medical Research Council of Australia project grants Declaration of interest: "None of the funding agencies played a role in the conception, design, or conduct of the study collection, management, analysis, and interpretation of the data or in the preparation, review, and approval of the manuscript." Author contacted, but requested information not provided.