title: Testing phase-specific self-efficacy beliefs in the context of dietary behaviour change.
abstract: BACKGROUND
  Self-efficacy is an important predictor of health behaviour change. Within the health action process approach (HAPA; Schwarzer, 2008), motivational and volitional self-efficacy can be distinguished. Motivational self-efficacy is assumed to serve as predictor of intention formation whereas volitional self-efficacy should be relevant for behaviour change. This study examined these assumptions in a sample with overweight and obese individuals. Moreover, we tested whether behavioural intentions moderate the association between volitional self-efficacy and behaviour.
  
  
  METHODS
  Overall, 373 overweight and obese individuals completed a baseline and six months later a follow-up questionnaire on HAPA variables and dietary behaviour.
  
  
  RESULTS
  A factor analysis confirmed the phase-specific separation of self-efficacy. Motivational self-efficacy emerged as predictor for behavioural intentions over and above other HAPA variables after six months, whereas volitional self-efficacy did not. Volitional self-efficacy interacted with intention in the prediction of behaviour, indicating that volitional self-efficacy is only beneficial for individuals with high levels of intentions.
  
  
  CONCLUSIONS
  The results provide evidence for the phase-specific distinction of self-efficacy in the context of dietary change in an overweight or obese sample. Thus, differentiating between motivational and volitional self-efficacy beliefs should be considered when developing future interventions of dietary change.
authors: Department of Psychology, University of Zurich, Zürich, Switzerland. sibylle.ochsner@psychologie.uzh.ch
authors: Sibylle
authors: S
authors: Ochsner
authors: Urte
authors: U
authors: Scholz
authors: Rainer
authors: R
authors: Hornung
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018752:Diet, Fat-Restricted / Q000523:psychology* / Q000706:statistics & numerical data; D015987:Effect Modifier, Epidemiologic; D005247:Feeding Behavior / Q000523:psychology; D005260:Female; D005544:Forecasting; D015438:Health Behavior; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D033182:Intention; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009042:Motivation; D050177:Overweight / Q000178:diet therapy* / Q000453:epidemiology / Q000523:psychology*; D020377:Self Efficacy; D013223:Statistics as Topic; D011795:Surveys and Questionnaires; D013997:Time Factors; D014836:Volition; D055815:Young Adult