To evaluate the effectiveness of the Theory of Planned Behavior (TPB) in understanding and predicting adolescents' SSB consumption, identify which constructs are the most important when evaluating SSB consumption in adolescents, and determine whether and how adolescents' beverage choices are influenced by parents' reactions to their beverage choices.
Measurements for this cross-sectional study included four record-assisted 24-hour dietary recalls and responses to an SSB-specific TPB questionnaire from 100 adolescents. Consenting parents completed a beverage intake questionnaire, a TPB questionnaire, and the Parent Response to Beverage Choice Questionnaire.
The TPB explained 34% of the variance in adolescents' and parents' intention to limit SSBs to <1cup/day. Parents' perceived behavioral control (b=1.35; P=0.002) and adolescents' subjective norms (b=0.57; P=0.001) were the strongest predictors of intention, and intention was the strongest predictor of SSB consumption in both adolescents and parents (b=–37 [P=0.026] and b=–49 [P=0.003], respectively). The TPB explained more variance in parent SSB consumption (R2=0.38) than adolescents (R2=0.22). Parents did more discouraging of SSBs and encouraging of non-SSBs. Adolescents' intention to limit SSB consumption moderated the relationship between parents' reactions encouraging SSBs and adolescents' predicted SSB consumption (P=0.021).
The TPB explained a small but significant amount of variance in adolescents' SSB consumption. When addressing adolescent SSB intake, people in addition to parents may influence their intentions and SSB consumption.