title: Effect of adherence to self-monitoring of diet and physical activity on weight loss in a technology-supported behavioral intervention.
abstract: BACKGROUND
  Examination of mediating behavioral factors could explain how an intervention works and thus provide guidance to optimize behavioral weight-loss programs. This study examined the mediating role of adherence to self-monitoring of diet and physical activity on weight loss in a behavioral weight-loss trial testing the use of personal digital assistants (PDA) for self-monitoring.
  
  
  METHODS
  Mediation analysis was conducted to examine the possible mediating role of adherence to self-monitoring of diet and physical activity between treatments using varying self-monitoring methods (paper record, PDA, and PDA with daily tailored feedback messages) and weight loss.
  
  
  RESULTS
  The sample (N = 210) was predominantly white (78%) and female (85%). Compared to a paper record, using a PDA for self-monitoring diet (P = 0.027) and physical activity (P = 0.014) had significant direct effects on weight loss at 12 months, as well as a significant indirect effect on outcomes through improved adherence to self-monitoring (P(S) < 0.001). Receiving an automated daily feedback message via PDA only had a significant indirect effect on weight through self-monitoring adherence to diet (P = 0.004) and physical activity (P = 0.002).
  
  
  CONCLUSIONS
  Adherence to self-monitoring of diet and physical activity is important as the underlying mechanism in this technology-supported behavioral weight-loss intervention.
authors.affiliation: School of Nursing, University of Texas Health Science Center at Houston, Houston, TX.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: Susan M
authors.initials: SM
authors.lastname: Sereika
authors.forename: Eileen R
authors.initials: ER
authors.lastname: Chasens
authors.forename: Linda J
authors.initials: LJ
authors.lastname: Ewing
authors.forename: Judith T
authors.initials: JT
authors.lastname: Matthews
authors.forename: Lora E
authors.initials: LE
authors.lastname: Burke