title: Determinants of successful weight loss after using a commercial web-based weight reduction program for six months: cohort study.
abstract: BACKGROUND
  The Internet is widely available and commonly used for health information; therefore, Web-based weight loss programs could provide support to large parts of the population in self-guided weight loss. Previous studies showed that Web-based weight loss interventions can be effective, depending on the quality of the program. The most effective program tools are visual progress charts or tools for the self-monitoring of weight, diet, and exercises. KiloCoach, a commercial program currently available in German-speaking countries, incorporates these features. A previous investigation showed that the program effectively supports users in losing weight.
  
  
  OBJECTIVE
  We investigated weight loss dynamics stratified by weight loss success after 6-month use of KiloCoach. Furthermore, we analyzed possible associations between intensity of program use and weight loss. The results are intended for tailoring user recommendations for weight-loss Internet platforms.
  
  
  METHODS
  Datasets of KiloCoach users (January 1, 2008 to December 31, 2011) who actively used the platform for 6 months or more were assigned to this retrospective analysis. Users (N=479) were 42.2% men, mean age of 44.0 years (SD 11.7), with a mean body mass index (BMI) of 31.7 kg/m² (SD 3.2). Based on the weight loss achieved after 6 months, 3 success groups were generated. The unsuccessful group lost <5%, the moderate success group lost 5%-9.9%, and the high success group lost ≥10% of their baseline body weight. At baseline, the unsuccessful (n=261, 54.5%), moderate success (n=133, 27.8%), and high success (n=85, 17.8%) groups were similar in age, weight, BMI, and gender distribution.
  
  
  RESULTS
  After 6 months, the unsuccessful group lost 1.2% (SD 2.4), the moderate success group lost 7.4% (SD 1.5), and the high success group lost 14.2% (SD 3.8) of their initial weight (P<.001). Multivariate regression showed that early weight loss (weeks 3-4), the total number of dietary protocols, and the total number of weight entries were independent predictors for 6-month weight reduction (all P<.001) explaining 52% of the variance in weight reduction. Sensitivity analysis by baseline carried forward method confirmed all independent predictors of 6-month weight loss and reduced the model fit by only 11%. The high success group lost weight faster and maintained weight loss more efficiently than the other groups (P<.001). Early weight loss was associated with weight maintenance after 1 year and 2 years (both P<.001). Weight dynamics did not differ between men and women over 6 months when adjusted for baseline and usage parameters (P=.91). The percentage of male long-term users was unusually high (42.2%).
  
  
  CONCLUSIONS
  Our results suggest that early weight loss and close program adherence (ie, 5 dietary protocols per week and weekly entering of current weight), especially in the early phase of program usage, can improve weight loss outcome.
authors.affiliation: The Division of Nutritional Medicine, Department of Gastroenterology and Hepatology, Charité- Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Elisa
authors.initials: E
authors.lastname: Postrach
authors.forename: Rosa
authors.initials: R
authors.lastname: Aspalter
authors.forename: Ulf
authors.initials: U
authors.lastname: Elbelt
authors.forename: Michael
authors.initials: M
authors.lastname: Koller
authors.forename: Rita
authors.initials: R
authors.lastname: Longin
authors.forename: Jörg-Dieter
authors.initials: JD
authors.lastname: Schulzke
authors.forename: Luzia
authors.initials: L
authors.lastname: Valentini
mesh_terms: D000328:Adult; D015992:Body Mass Index; D015331:Cohort Studies; D005260:Female; D006801:Humans; D020407:Internet; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D020377:Self Efficacy; D012984:Software; D015431:Weight Loss
keywords: Internet; efficiency; obesity; overweight; preventive health services; program evaluation; sex; weight loss; weight reduction program