Enhancing the theory of planned behavior with social reactive constructs in explaining adolescents' dietary behaviors

The increasing prevalence of poor dietary habits among adolescents presents significant health challenges, highlighting the need for effective behavioral interventions. The Theory of Planned Behavior (TPB), though widely used for rational behaviors, falls short in explaining adolescent behaviors due to their limited behavioral control. The Prototype Willingness Model (PWM) proposes social-reactive constructs to explain impulsive behaviors. This study aims to evaluate the enhanced explanatory power of social reactive constructs of PWM on adolescent dietary behaviors, alongside TPB.

The study employed a two-wave cross-sectional design with 638 middle school students. Their status regarding the TPB and PWM constructs was assessed using a self-administered questionnaire and their dietary intake was assessed using a food frequency questionnaire. Hierarchical regression analyses were applied to examine the added effects of social reactive constructs beyond TPB.

Integrating the social reaction constructs of the PWM with the TPB constructs enhanced the explanation of adolescents' dietary behaviors. The final model explained 14.7 %, 14.7 %, and 12.1 % of the variances in fruit and vegetable intake, sugar-sweetened beverage intake, and energy-dense food intake, respectively. Prototype favorability emerged as the strongest factor across all three dietary behaviors (β = 0.42, 0.09, 0.15; all P < 0.01). Behavioral willingness significantly predicted sugar-sweetened beverage intake and energy-dense food intake (β = 0.06, 0.07; all P < 0.01), while intention did not.

Incorporating social reactive constructs into TPB enhanced the explanatory power in predicting adolescent dietary behaviors. This integration offers valuable insights for designing targeted interventions to improve dietary habits among adolescents.