title: Diets with high or low protein content and glycemic index for weight-loss maintenance.
abstract: BACKGROUND
  Studies of weight-control diets that are high in protein or low in glycemic index have reached varied conclusions, probably owing to the fact that the studies had insufficient power.
  
  
  METHODS
  We enrolled overweight adults from eight European countries who had lost at least 8% of their initial body weight with a 3.3-MJ (800-kcal) low-calorie diet. Participants were randomly assigned, in a two-by-two factorial design, to one of five ad libitum diets to prevent weight regain over a 26-week period: a low-protein and low-glycemic-index diet, a low-protein and high-glycemic-index diet, a high-protein and low-glycemic-index diet, a high-protein and high-glycemic-index diet, or a control diet.
  
  
  RESULTS
  A total of 1209 adults were screened (mean age, 41 years; body-mass index [the weight in kilograms divided by the square of the height in meters], 34), of whom 938 entered the low-calorie-diet phase of the study. A total of 773 participants who completed that phase were randomly assigned to one of the five maintenance diets; 548 completed the intervention (71%). Fewer participants in the high-protein and the low-glycemic-index groups than in the low-protein-high-glycemic-index group dropped out of the study (26.4% and 25.6%, respectively, vs. 37.4%; P=0.02 and P=0.01 for the respective comparisons). The mean initial weight loss with the low-calorie diet was 11.0 kg. In the analysis of participants who completed the study, only the low-protein-high-glycemic-index diet was associated with subsequent significant weight regain (1.67 kg; 95% confidence interval [CI], 0.48 to 2.87). In an intention-to-treat analysis, the weight regain was 0.93 kg less (95% CI, 0.31 to 1.55) in the groups assigned to a high-protein diet than in those assigned to a low-protein diet (P=0.003) and 0.95 kg less (95% CI, 0.33 to 1.57) in the groups assigned to a low-glycemic-index diet than in those assigned to a high-glycemic-index diet (P=0.003). The analysis involving participants who completed the intervention produced similar results. The groups did not differ significantly with respect to diet-related adverse events.
  
  
  CONCLUSIONS
  In this large European study, a modest increase in protein content and a modest reduction in the glycemic index led to an improvement in study completion and maintenance of weight loss. (Funded by the European Commission; ClinicalTrials.gov number, NCT00390637.).
authors.affiliation: Department of Human Nutrition, Faculty of Life Sciences, University of Copenhagen, Copenhagen, Denmark. tml@life.ku.dk
authors.forename: Thomas Meinert
authors.initials: TM
authors.lastname: Larsen
authors.forename: Stine-Mathilde
authors.initials: SM
authors.lastname: Dalskov
authors.forename: Marleen
authors.initials: M
authors.lastname: van Baak
authors.forename: Susan A
authors.initials: SA
authors.lastname: Jebb
authors.forename: Angeliki
authors.initials: A
authors.lastname: Papadaki
authors.forename: Andreas F H
authors.initials: AF
authors.lastname: Pfeiffer
authors.forename: J Alfredo
authors.initials: JA
authors.lastname: Martinez
authors.forename: Teodora
authors.initials: T
authors.lastname: Handjieva-Darlenska
authors.forename: Marie
authors.initials: M
authors.lastname: Kunešová
authors.forename: Mats
authors.initials: M
authors.lastname: Pihlsgård
authors.forename: Steen
authors.initials: S
authors.lastname: Stender
authors.forename: Claus
authors.initials: C
authors.lastname: Holst
authors.forename: Wim H M
authors.initials: WH
authors.lastname: Saris
authors.forename: Arne
authors.initials: A
authors.lastname: Astrup
mesh_terms: D015746:Abdominal Pain / Q000209:etiology; D000328:Adult; D015415:Biomarkers / Q000652:urine; D015992:Body Mass Index; D050528:Diet, Carbohydrate-Restricted; D018753:Diet, Protein-Restricted / Q000009:adverse effects; D004038:Diet, Reducing; D004044:Dietary Proteins / Q000008:administration & dosage*; D038321:Glycemic Index; D006801:Humans; D057194:Intention to Treat Analysis; D009765:Obesity / Q000178:diet therapy; D050177:Overweight / Q000178:diet therapy*; D010349:Patient Compliance; D015431:Weight Loss
chemical_list: D015415:Biomarkers; D004044:Dietary Proteins