Gardner 2007.

Study characteristics
Methods	Review comparison(s) addressed by this study: 1 Study design: RCT, parallel, single‐centre (1) Trial registry number: NCT00079573 Total number of trial arms: 4 Year trial started: 2003 Sample size calculation: Yes Outcome(s) used for sample size calculation: Weight loss Duration of run‐in period (weeks): NA What was the duration of the weight loss phase: 12 months What was the duration of the weight maintenance phase: NA Other notes about methods: NA
Participants	Country and setting: USA, outpatient research centre in Stanford Eligibility criteria: Participants were women aged 25 to 50 with a BMI of 27 to 40 kg/m2, with stable body weight for the past two months and stable medication for the past three months. Participants were excluded if they self‐reported hypertension which was not controlled with antihypertensive medication; had diabetes or heart, liver or renal disease; cancer or active neoplasms; uncontrolled or untreated hyperthyroidism; using medications which affect weight; consume three or more alcoholic drinks a day; were pregnant, lactating or had not menstruated in the past 12 months or if they planned to become pregnant in the next year. Type 2 diabetes at baseline: No Impaired glucose tolerance at baseline: Unclear Cardiovascular conditions/risk factors/events at baseline: No Gender: Female Total number randomised: 311 Total attrition in trial: 62 Treatment diet Participants randomised: 77 Participants withdrawn (voluntary): 6 Total attrition: 9 Control diet: Participants randomised: 79 Participants withdrawn (voluntary): 12 Total attrition: 18 Baseline data treatment diet: Randomised participants not included: None Age (years): mean (SD) 42 (5) Gender distribution (as reported): female 100%, male 0% Weight (kg): mean (SD) 86 (13) BMI (kg/m2): mean (SD) 32 (4) DBP (mmHg): mean (SD) 75 (8) SBP (mmHg): mean (SD) 118 (11) HbA1c (%): NR LDL (mmol/L): mean (SD) 2.82 (0.75) HDL (mmol/L): mean (SD) 1.37 (0.36) Non‐HDL (mmol/L): mean (SD) 3.47 (0.85) TC (mmol/L): NR TG (mmol/L): mean (SD) 1.41 (0.88) Baseline data control diet: Randomised participants not included: None Age (years): mean (SD) 40 (7) Gender distribution (as reported): female 100%, male 0% Weight (kg): mean (SD) 85 (14) BMI (kg/m2): mean (SD) 31 (4) DBP (mmHg): mean (SD) 75 (9) SBP (mmHg): mean (SD) 116 (12) HbA1c (%): NR LDL (mmol/L): mean (SD) 2.69 (0.75) HDL (mmol/L): mean (SD) 1.32 (0.28) Non‐HDL (mmol/L): mean (SD) 3.29 (0.88) TC (mmol/L): NR TG (mmol/L): mean (SD) 1.34 (0.82) 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: Different ‐ ad libitum in treatment diet and restricted in control diet Treatment diet: Name (as reported) and brief description: Atkins diet. Aimed for 20 g/d or less of carbohydrates for induction of 2 to 3 months and 50 g/d for the 'ongoing weight loss' phase, ad libitum energy prescription Treatment diet type (carbohydrate‐fat‐protein): Very low8‐12w to low40‐44w‐unclear‐unclear Exercise component? No Recipients: Overweight or obese premenopausal women, aged mean (SD) 42 (5) years with BMI mean (SD) 32 (4) and weight mean (SD) 86 (13) kg, with or without metabolic syndrome, n (%) 22/77 (29%) Why? Low‐carbohydrate diets ad libitum diets may be at least as effective as traditional low‐fat, high‐carbohydrate diets for weight loss up to one year. The evidence to date is limited. What (materials)? Dr Atkins' New Diet Revolution (Atkins 2002). What (procedures)? Participants in this diet group aimed for the consumption of 20 g/d or less of carbohydrate for 'induction' (usually 2‐3 months) and 50 g/d or less of carbohydrate for the subsequent 'ongoing weight loss' phase. Participants were assigned their diet book, attended regular classes covering the contents of the book and were administered unannounced dietary intake and energy expenditure questionnaires. Who provided? A registered dietitian led the classes and covered a portion of the book's contents per session so it would be complete at the end of the contact period. Unannounced dietary and exercise data were collected by persons trained and certified by the Nutrition Coordinating Centre. How and where? Class sessions were held face‐to‐face and in groups, location NR. Unannounced dietary and exercise data were collected by telephone. When and how much? Class sessions were one hour each and occurred every week for eight weeks. Unannounced dietary and exercise data were collected at baseline and at 2, 6 and 12 months. This entailed recall of three days (two weekdays and one weekend day, preferably non‐consecutive) of dietary intake as well as seven days of physical activity. Strategies to improve or maintain fidelity; tailoring and modification: Strategies included email and telephone reminders for appointments, email or telephone contact from staff between the 2‐ and 6‐month and between the 6‐ and 12‐month data collection points, and incentive payments of $25, $50, and $75 for completing the 2‐, 6‐, and 12‐month data collection, respectively. A ‘Food Amounts Booklet’ was used to assist participants with portion size estimation during dietary recalls. Unannounced dietary and exercise recalls, group sessions, measurement of body weight as part of study outcomes Extent of intervention fidelity: Dietary adherence scores calculated as the difference between reported and recommended daily carbohydrate intake (< = 20 g carbohydrate per day during the first two months; and <= 50 g carbohydrate per day for the subsequent 10 months), using the average of three non‐consecutive 24‐h dietary recalls at each time point. A lower score reflects better adherence. Adherence score, means (SD): at 2 months, 35.2 (32.7); at 6 months, 62.6 (64.7); at 12 months, 85.8 (70.5). In all 4 diet groups, 85% to 89% of participants attended at least 75% of their assigned classes (>= 6 of 8). Attendance was not different by diet group (P = 0.68). Concomitant interventions: Participants on antihypertensive medications whose blood pressure was stable, as well as those on treatment for hyperthyroidism vs "were not taking medications for cardiac risk factors"? Control diet: Name (as reported) and brief description: LEARN diet. Prudent diet that included 55 to 60% of energy from carbohydrates and less than 10% energy from saturated fat, unspecified caloric restriction, increased exercise Control diet type (carbohydrate‐fat‐protein): Balanced‐unclear‐unclear Exercise component? Yes Recipients: Overweight or obese premenopausal women, aged mean (SD) 40 (7) years with BMI mean (SD) 31 (4) and weight mean (SD) 85 (14) kg, with or without metabolic syndrome, n (%) 29/79 (37) Why? This diet is based on national American guidelines. Such national guidelines have been challenged by proponents of low‐carbohydrate diets, but limited evidence is currently available. What (materials)? Participants were instructed to follow a prudent diet that included 55% to 60% energy from carbohydrate and less than 10%energy from saturated fat, caloric restriction, increased exercise, and behaviour modification strategies. The LEARN program is intended to be a 16‐week programme and, therefore, the 8 weeks of guidance in this study. Participants were assigned to a diet book (the LEARN Manual for Weight Management). What (procedures)? Participants were assigned their diet book, attended regular classes covering the contents of the book and were administered unannounced dietary intake and energy expenditure questionnaires. Participants were instructed to follow a prudent diet that included 55% to 60% energy from carbohydrate and less than 10% energy from saturated fat, caloric restriction, increased exercise, and behaviour modification strategies. Who provided? A registered dietitian led the classes and covered a portion of the book's contents per session so it would be complete at the end of the contact period. Unannounced dietary and exercise data were collected by persons trained and certified by the Nutrition Coordinating Centre. How and where? Class sessions were held face‐to‐face and in groups, location NR. Unannounced dietary and exercise data were collected by telephone. When and how much? Class sessions were one hour each and occurred every week for eight weeks. Since the LEARN program spans 16 weeks, therefore these sessions reflected an accelerated timespan. Unannounced dietary and exercise data were collected at baseline and at 2, 6 and 12 months. This entailed recall of three days (two weekdays and one weekend day, preferably non‐consecutive) of dietary intake as well as seven days of physical activity. Strategies to improve or maintain fidelity; tailoring and modification: Strategies included email and telephone reminders for appointments, email or telephone contact from staff between the 2‐ and 6‐month and between the 6‐ and 12‐month data collection points, and incentive payments of $25, $50, and $75 for completing the 2‐, 6‐, and 12‐month data collection, respectively. A ‘Food Amounts Booklet’ was used to assist participants with portion size estimation during dietary recalls. Unannounced dietary and exercise recalls, group sessions, measurement of body weight as part of study outcomes Extent of intervention fidelity: Dietary adherence scores could not be calculated due to the multiple dimensions of the intervention programme's recommended goals. In all 4 diet groups, 85% to 89% of participants attended at least 75% of their assigned classes (>= 6 of 8). Attendance was not different by diet group (P = 0.68). Concomitant interventions: Participants on antihypertensive medications whose blood pressure was stable, as well as those on treatment for hyperthyroidism vs "were not taking medications for cardiac risk factors"?
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: 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 (mmom/L) at ≥ 12 months: Yes Change in total cholesterol (TC) (mmol/L) at ≥ 12 months: No 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: None Trial funded by: British Diabetic Association and the International Sugar Research Foundation Inc. Declaration of interest: "None reported."