title: Effective techniques in healthy eating and physical activity interventions: a meta-regression.
abstract: OBJECTIVE
  Meta-analyses of behavior change (BC) interventions typically find large heterogeneity in effectiveness and small effects. This study aimed to assess the effectiveness of active BC interventions designed to promote physical activity and healthy eating and investigate whether theoretically specified BC techniques improve outcome.
  
  
  METHODS
  Interventions, evaluated in experimental or quasi-experimental studies, using behavioral and/or cognitive techniques to increase physical activity and healthy eating in adults, were systematically reviewed. Intervention content was reliably classified into 26 BC techniques and the effects of individual techniques, and of a theoretically derived combination of self-regulation techniques, were assessed using meta-regression.
  
  
  METHODS
  Valid outcomes of physical activity and healthy eating.
  
  
  RESULTS
  The 122 evaluations (N = 44,747) produced an overall pooled effect size of 0.31 (95% confidence interval = 0.26 to 0.36, I(2) = 69%). The technique, "self-monitoring," explained the greatest amount of among-study heterogeneity (13%). Interventions that combined self-monitoring with at least one other technique derived from control theory were significantly more effective than the other interventions (0.42 vs. 0.26).
  
  
  CONCLUSIONS
  Classifying interventions according to component techniques and theoretically derived technique combinations and conducting meta-regression enabled identification of effective components of interventions designed to increase physical activity and healthy eating.
authors.affiliation: Centre for Outcomes Research and Effectiveness, University College London, UK. s.michie@ucl.ac.uk
authors.forename: Susan
authors.initials: S
authors.lastname: Michie
authors.forename: Charles
authors.initials: C
authors.lastname: Abraham
authors.forename: Craig
authors.initials: C
authors.lastname: Whittington
authors.forename: John
authors.initials: J
authors.lastname: McAteer
authors.forename: Sunjai
authors.initials: S
authors.lastname: Gupta
mesh_terms: D015444:Exercise; D005247:Feeding Behavior; D005260:Female; D015438:Health Behavior; D006293:Health Promotion; D006801:Humans; D008297:Male