title: Association between Self-Weighing and Percent Weight Change: Mediation Effects of Adherence to Energy Intake and Expenditure Goals.
abstract: BACKGROUND
  To date, no investigators have examined electronically recorded self-weighing behavior beyond 9 months or the underlying mechanisms of how self-weighing might impact weight change.
  
  
  OBJECTIVE
  Our aims were to examine electronically recorded self-weighing behavior in a weight-loss study and examine the possible mediating effects of adherence to energy intake and energy expenditure (EE) goals on the association between self-weighing and weight change.
  
  
  METHODS
  This was a secondary analysis of the self-efficacy enhancement arm of the Self Efficacy Lifestyle Focus (SELF) trial, an 18-month randomized clinical trial.
  
  
  METHODS
  The study was conducted at the University of Pittsburgh (2008-2013). Overweight or obese adults with at least one additional cardiovascular risk factor were eligible.
  
  
  METHODS
  Participants in the self-efficacy enhancement arm were given a scale (Carematix, Inc) and instructed to weigh themselves at least 3 days per week or every other day. The scale date- and time-stamped each weighing episode, storing up to 100 readings.
  
  
  METHODS
  Weight was assessed every 6 months. Adherence to energy intake and EE goals was calculated on a weekly basis using paper diary data.
  
  
  METHODS
  Linear mixed modeling and mediation analyses were used.
  
  
  RESULTS
  The sample (n=55) was 80% female, 69% non-Hispanic white, mean (standard deviation) age was 55.0 (9.6) years and body mass index (calculated as kg/m2) was 33.1 (3.7). Adherence to self-weighing declined over time (P<0.001). From baseline to 6 months, there was a significant mediation effect of adherence to energy intake (P=0.02) and EE goals (P=0.02) on the association between adherence to self-weighing and percent weight change. Mediation effects were not significant during the second and third 6-month periods of the study.
  
  
  CONCLUSIONS
  Objectively measured adherence to self-weighing declined over 18 months. During the first 6 months, self-weighing directly impacted weight change and indirectly impacted weight change through changes in energy intake and EE.
authors.forename: Yaguang
authors.initials: Y
authors.lastname: Zheng
authors.forename: Susan M
authors.initials: SM
authors.lastname: Sereika
authors.forename: Linda J
authors.initials: LJ
authors.lastname: Ewing
authors.forename: Cynthia A
authors.initials: CA
authors.lastname: Danford
authors.forename: Martha Ann
authors.initials: MA
authors.lastname: Terry
authors.forename: Lora E
authors.initials: LE
authors.lastname: Burke
mesh_terms: D001519:Behavior; D015992:Body Mass Index; D001835:Body Weight; D002318:Cardiovascular Diseases; D002149:Energy Intake; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000628:therapy; D050177:Overweight / Q000628:therapy; D012307:Risk Factors; D012648:Self Care; D020377:Self Efficacy; D015431:Weight Loss
keywords: Behavior; Energy expenditure; Energy intake; Self-weighing; Weight loss