Influence of behavioral theory on fruit and vegetable intervention effectiveness among children: a meta-analysis.

OBJECTIVE: To test the hypotheses that interventions clearly based on theory, multiple theories, or a formal intervention planning process will be more effective in changing fruit and vegetable consumption among children than interventions with no behavioral theoretical foundation. DESIGN: Systematic review and meta-analysis. SETTING: Identification of articles in PubMed, PsycInfo, Medline, Cochrane Collaborative database, and existing literature reviews and meta-analyses. PARTICIPANTS: Children aged 2-18 years. INTERVENTIONS: Change in fruit and/or vegetable consumption in dietary change interventions. METHODS: Meta-analysis, meta-regression analysis, and summary reporting for articles. CONCLUSIONS AND IMPLICATIONS: Predicating an intervention on behavioral theory had a small to moderate enhancement (P < .001) of outcome effectiveness. Differences in mean Hedges' g effect sizes between theory and non-theory interventions were 0.232 for fruit, 0.043 for vegetables, and 0.333 for fruit and vegetables combined. There was mixed support, however, for enhanced dietary change with multiple theories or a formal planning process. After controlling for study quality, theory use was related only to vegetable consumption (ß = 0.373; P < .001). More research is needed on theory's influences on dietary behaviors to guide future interventions among children. More research is also needed to identify what may be effective practical- or experience-based procedures that complement theory, to incorporate into interventions.