Crystal Smit

An Integrated Model 3 47 BACKGROUND Obesity among young adolescents remains a public health priority worldwide (WHO, 2020). Critical contributors of youth overweight and obesity include the consumption of highly energy-dense foods and sugar-sweetened beverages (Hu, 2013; Stelmach-Mardas et al., 2016). Researchers have shown that increasing fruit, vegetable, and water consumption can be effective ways to decrease overweight and obesity (Hu, 2013; Lin & Morrison, 2002). To improve interventions for obesity prevention, it is essential to gain insight into the mechanisms predicting dietary behaviors. Therefore, to bring guidance to the design and implementation of future studies, this paper integrates elements of three dominant theoretical constructs to predict young adolescents’ consumption of fruit, vegetables, and water: planned behavior, social norms, and intrinsic motivation. One of the most widely used models to predict behavioral change is the theory of planned behavior, which asserts that an individual’s behavioral intention is the most important predictor of behavioral change (Ajzen, 1985; Conner, Norman, & Bell, 2002). According to the theory of planned behavior, an individual’s intention to perform the behavior is predicted by (a) attitude toward the behavior (the self-perceived evaluation of the behavior), (b) self-efficacy (an individual’s belief that he or she is capable and in control of the behavior), and (c) subjective norms (an individual’s perceptions of what others consider appropriate concerning the behavior). In turn, behavioral intention predicts the individual’s actual behavior (Ajzen, 1985; Conner et al., 2002). Research investigating the theory of planned behavior in relation to dietary behaviors is mostly cross-sectional and has yielded mixed findings. Several cross- sectional studies have confirmed theory of planned behavior assumptions, finding that attitude, self-efficacy, and subjective norms relate to intentions that, in turn, relate to dietary behaviors (for review, see Riebl et al., 2015). However, longitudinal research has shown mixed findings in the prediction of changes in long-term dietary behaviors (for review, see Shaikh, Yaroch, Nebeling, Yeh, & Resnicow, 2008). This so-called “intention–behavior” gap reflects a common observation in