Decaying behavioral effects in a randomized, multi-year fruit and vegetable intake intervention

Objective. To examine the effects of a multi-component, theory-based, 2.5-year intervention on children's fruit and vegetable consumption, preferences, knowledge and body mass index. Methods. Four inner city elementary schools in the Northeastern United States were randomized to an intervention (n = 149) or control group (n = 148) in 2005. Fruit and vegetable consumption during school lunch (measured by plate waste), preferences, and knowledge, as well as body mass index, were assessed five times across 3.5 years (pre-intervention, spring 2006, 2007, 2008 and 2009). Hierarchical linear modeling was used to analyze program outcomes. Results. At the first post-test assessment, children in the experimental group ate 0.28 more servings/lunch of fruit and vegetable relative to children in the control group and changes in fruit and vegetable consumption were found in each year throughout the program. However, this effect declined steadily across time so that by the delayed one-year follow-up period there was no difference between the groups in fruit and vegetable consumption. There were persistent intervention effects on children's knowledge. There were no effects on fruit and vegetable preferences and body mass index throughout the study. Conclusion. Although there was initial fruit and vegetable behavior change, annual measurements indicated a gradual decay of behavioral effects. These data have implications for the design of school-based fruit and vegetable interventions. (C) 2011 Elsevier Inc. All rights reserved.