Juanola‐Falgarona 2014.

Study characteristics
Methods	Review comparison(s) addressed by this study: 1 Study design: RCT, parallel, single‐centre (1) Trial registry number: ISRCTN54971867 Total number of trial arms: 3 Year trial started: 2010 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: 6 months What was the duration of the weight maintenance phase: NA Other notes about methods: NA
Participants	Country and setting: Spain, outpatient university hospital in Reus Eligibility criteria: Participants were aged between 30 and 60 years with BMI between 27 and 35 kg/m2. Participants were excluded if they had uncontrolled type 2 diabetes (defined as HbA1c above 8%), systolic blood pressure or diastolic blood pressure above 159 or 99 mmHg, respectively, plasma LDL concentration above 160 mg/dL, plasma triglyceride concentration above 400 mg/dL; suspicion of secondary cause of obesity; presence of an inflammatory or chronic obstructive pulmonary disease, infection or active neoplasm; active endocrine or haematologic disease at the time of the study; blood leukocyte count ≥ 11 x 10^6 cells; were using anti‐inflammatory drugs, steroids, hormones or antibiotics which could affect study outcomes; had changes in medication for lipids, diabetes or hypertension in the past three months; were alcoholic or drug‐dependent (excluding tobacco); had a restrictive diet or more than 5 kg weight loss in the past three months; any medical condition which advised against inclusion; problems understanding the study, or reservations about adhering to the study diet. Type 2 diabetes at baseline: No ‐ confirmed by author: "T2D was not an exclusion criteria to participate in the study but, at the end, none of the participants had T2D". Impaired glucose tolerance at baseline: Unclear Cardiovascular conditions/risk factors/events at baseline: Unclear Gender: Mixed Total number randomised: 122 Total attrition in trial: 18 Treatment diet Participants randomised: 41 Participants withdrawn (voluntary): 1 Total attrition: 5 Control diet: Participants randomised: 40 Participants withdrawn (voluntary): 0 Total attrition: 9 Baseline data treatment diet: Randomised participants not included: 1/41 Age (years): mean (SE) 44.0 (1.3) Gender distribution (as reported): female 33/40 (83%), male 7/40 (17%) Weight (kg): mean (SE) 82.7 (1.6) BMI (kg/m2): mean (SE) 30.8 (0.3) DBP (mmHg): mean (SE) 81.2 (1.5) SBP (mmHg): mean (SE) 128.0 (2.4) HbA1c (%): NR LDL (mmol/L): mean (SE) 3.15 (0.10) HDL (mmol/L): mean (SE) 1.47 (0.05) Non‐HDL (mmol/L): NR TC (mmol/L): mean (SE) 5.13 (0.13) TG (mmol/L): mean (SE) 1.03 (0.70) Baseline data control diet: Randomised participants not included: 0/40 Age (years): mean (SE) 44.1 (1.3) Gender distribution (as reported): female 31/40 (78%), male 9/40 (22%) Weight (kg): mean (SE) 83.5 (1.7) BMI (kg/m2): mean (SE) 30.8 (0.3) DBP (mmHg): mean (SE) 82.8 (1.4) SBP (mmHg): mean (SE) 131.3 (2.2) HbA1c (%): NR LDL (mmol/L): mean (SE) 2.95 (0.10) HDL (mmol/L): mean (SE) 1.37 (0.05) Non‐HDL (mmol/L): NR TC (mmol/L): mean (SE) 4.82 (0.13) TG (mmol/L): mean (SE) 0.98 (0.85) Group differences at baseline: Yes Characteristic(s) with significant group difference and relevant statistic: characteristic 1: HOMA‐BCF (P = 0.037) and adiponectin (P = 0.020); NR between which arms 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‐GI diet. Advised to consume 42% of energy from high‐GI carbohydrates, 18% from protein and 40% from fat. GI = 62. Energy prescription was determined by subtracting 500 kcal/d from the total estimated baseline energy intake. Treatment diet type (carbohydrate‐fat‐protein): Low‐high‐balanced Exercise component? No Recipients: Healthy adults (83% female, 17% male), with a mean age of 44.0 (8.2) years and a mean BMI of 30.8 (1.9) kg/m2, with or without hypertension (5/40; 13%), hypercholesterlaemia (2/40; 5%) Why? To determine whether an isocaloric diet, rich in high‐glycaemic index carbohydrates has a smaller effect on weight loss, compared to a diet, rich in low‐glycaemic index carbohydrates. "...low‐carbohydrate diets were related to better improvements in the lipid profile. Nonetheless, in a pooled analysis that was based on observational studies, low‐carbohydrate diets seemed to be associated with increased risk of all‐cause mortality." What (materials)? "...subjects received a dossier containing a leaflet with written general dietary recommendations, biweekly menus, and seasonal receipts. An informative website was available for all participants (http://www.glyndiet.org/)." What (procedures)? "Participants were encouraged to eat whole grain cereals and pulses as the base of their diet, avoid the rice and potatoes, and were also recommended to select specific types of fruit (apple, orange, peach) and vegetables (courgette, tomato, onion) with low GI, avoiding the ripe pieces. They were advised to reduce the time cooking of carbohydrate rich‐foods in order to maintain the low GI of the foods. The principal animal protein sources of the diet were white fish and white meat. In order to obtain the desired weight loss, a 500 kcal restriction in diet was applied to each participant. Total daily energy expenditure for each participant was estimated using the WHO (2001) equations corrected by the physical activity degree. Diets were designed at 1500, 1700, 2000, and 2500 kcal/d, and all participants were categorised as having one of the 4 categories of dietary energy content after subtracting 500 kcal/d of the total estimated energy intake to achieve a desired weight loss." Who provided? Dietitian How and where? Face‐to‐face personalised advice was given to each patient. When and how much? Individual examination visits at baseline, after 2 weeks and thereafter monthly. Unclear at which of these visits the intervention was reinforced. The study authors reported: "Across the visits, different evaluations and questionnaires were conducted to assess changes on anthropometry and the adherence to the intervention". Strategies to improve or maintain fidelity; tailoring and modification: "Dietary intake was estimated at baseline and at the 1st, 3th and 6th month of intervention by mean of 3‐day dietary records including two workdays and a weekend day. Subjects were encouraged to weigh the food that they eat; otherwise trained dietitians estimated weight using an illustrated book of food portions. Energy and nutrient intake were calculated from Spanish food composition tables. Values of GI for each food were extracted from the International Glycemic Index and Glycemic Load Values using glucose as the reference scale." Extent of intervention fidelity: NR Concomitant interventions: NR Control diet: Name (as reported) and brief description: Low‐fat diet. Advised to consume 52% of energy from high‐GI carbohydrates, 18% from protein and 30% from fat. GI = 65. Energy prescription was determined by subtracting 500 kcal/d from the total estimated baseline energy intake. Control diet type (carbohydrate‐fat‐protein): Balanced‐balanced‐balanced Exercise component? No Recipients: Healthy adults (78% female, 22% male), with a mean age of 44.1 (8.2) years and a mean BMI of 30.8 (1.9) kg/m2, with or without hypertension (5/40; 13%), hypercholesterlaemia (5/40; 13%) Why? To determine whether an isocaloric low‐fat diet, rich in high‐glycaemic index carbohydrates, has a smaller effect on weight loss, compared to a diet, rich in low‐glycaemic index carbohydrates What (materials)? "...subjects received a dossier containing a leaflet with written general dietary recommendations, biweekly menus, and seasonal receipts. An informative website was available for all participants (http://www.glyndiet.org/)." What (procedures)? Subjects randomised to a low‐fat diet were also advised to maintain a high‐GI diet but with lower fat content. Participants had to follow a low‐fat diet fulfilling the criteria defined by the American Heart Association (30% of energy from fat, 52% of energy from high‐glycaemic index carbohydrates, 18% of energy from proteins). Participants were encouraged to eat refined grain cereals, fruits (banana, kiwi, melon) and vegetables (carrot, green bean, cabbage) with high GI, and avoid pulses. Additionally, daily sugar was substituted by glucose in order to rise GI of this intervention. In this case, they were recommended to avoid red meat and blue fish due its high fat content and also recommended to eat low‐fat dairy products. In order to obtain the desired weight loss, a 500 kcal restriction in diet was applied to each participant. Total daily energy expenditure for each participant was estimated using the WHO (2001) equations corrected by the physical activity degree. Who provided? Dietitian How and where? Face‐to‐face personalised advice was given to each patient. When and how much? Individual examination visits at baseline, after 2 weeks and thereafter monthly. Unclear at which of these visits the intervention was reinforced. The study authors reported: " Across the visits, different evaluations and questionnaires were conducted to assess changes on anthropometry and the adherence to the intervention". Strategies to improve or maintain fidelity; tailoring and modification: "Dietary intake was estimated at baseline and at the 1st, 3th and 6th month of intervention by mean of 3‐day dietary records including two workdays and a weekend day. Subjects were encouraged to weigh the food that they eat; otherwise trained dieticians estimated weight using an illustrated book of food portions. Energy and nutrient intake were calculated from Spanish food composition tables. Values of GI for each food were extracted from theInternational Glycemic Index and Glycemic Load Values using glucose as the reference scale." Extent of intervention fidelity: NR Concomitant interventions: NR
Outcomes	Change in body weight (kg) at 3 to < 12 months: No Change in body weight (kg) at ≥ 12 months: No 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: 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: No Change in SBP (mmHg) at ≥ 12 months: No 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: No Change in HDL (mmol/L) at ≥ 12 months: No Change in non‐HDL (mmom/L) at ≥ 12 months: No Change in total cholesterol (TC) (mmol/L) at ≥ 12 months: No Change in triglycerides (or triacylglycerides) (TG) (mmol/L) at ≥ 12 months: No Participant‐reported adverse effects: No
Notes	Number and type of records(s): journal article Trial acronym/name: GLYNDIET Trial funded by: Institut d'Investigació Sanitaria Pere Virgili (PV11059S) and the Fondo de Investigación Sanitaria (PI120153) Declaration of interest: "None of the authors had a personal or financial conflict of interest."