title: Health messages to promote fruit and vegetable consumption at different stages: A match-mismatch design.
abstract: OBJECTIVE
  To examine the effectiveness of matching health messages promoting fruit and vegetable intake to the Health Action Process Approach stages of change.
  
  
  METHODS
  In a randomised controlled trial, 205 undergraduate students (non-intenders n = 123; intenders n = 82) were exposed to one of three health messages, targeted at non-intenders, intenders and controls.
  
  
  METHODS
  Three longitudinal assessments of stage, fruit and vegetable intake, and social-cognitive determinants were obtained.
  
  
  RESULTS
  Stage-specific effects of the interventions were confirmed. For self-efficacy, a stage by health message crossover interaction emerged, with both non-intenders and intenders in the matched conditions scoring higher in self-efficacy. Furthermore, in line with predictions, non-intenders in the matched condition showed higher risk perception, outcome expectancies, intention, and stage progression immediately after message exposure, and lower levels of action planning and coping planning a week later in the mismatched condition, but for these outcomes no differences across conditions were obtained among intenders. Multiple mediation analyses confirmed the facilitating role of self-efficacy and behavioural intention among non-intenders.
  
  
  CONCLUSIONS
  Stages should be considered when designing health messages, although more interactive interventions for intenders and extended measurement time frames may be required.
authors.affiliation: a Instituto Universitário de Lisboa (ISCTE-IUL), CIS-IUL , Lisboa , Portugal.
authors.forename: Cristina A
authors.initials: CA
authors.lastname: Godinho
authors.affiliation: b Faculdade de Psicologia , Universidade de Lisboa , Lisboa , Portugal.
authors.forename: Maria-João
authors.initials: MJ
authors.lastname: Alvarez
authors.affiliation: a Instituto Universitário de Lisboa (ISCTE-IUL), CIS-IUL , Lisboa , Portugal.
authors.forename: Maria Luísa
authors.initials: ML
authors.lastname: Lima
authors.affiliation: c Institute for Positive Psychology and Education , Australian Catholic University , Sydney , Australia.|d Freie Universität Berlin , Berlin , Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Schwarzer
mesh_terms: D000223:Adaptation, Psychological; D000293:Adolescent; D000328:Adult; D004032:Diet / Q000523:psychology* / Q000706:statistics & numerical data; D005260:Female; D005638:Fruit; D015438:Health Behavior; D058015:Health Communication / Q000379:methods*; D006293:Health Promotion / Q000379:methods*; D006801:Humans; D033182:Intention; D008297:Male; D011582:Psychological Theory; D012107:Research Design; D020377:Self Efficacy; D014675:Vegetables; D055815:Young Adult
keywords: fruit and vegetable intake; health message targeting; multiple mediation analyses; randomised controlled trial; stages of change