Nutrition Knowledge-Extended Theory of Planned Behavior as a Conceptual Framework for Understanding Ultra-Processed Food Consumption Among Students of Northern Border University, Saudi Arabia

Aims: This study aimed to examine the influence of nutrition knowledge on the pathways of the Theory of Planned Behavior (TPB) — specifically attitudes, subjective norms, perceived behavioral control (PBC), intention, and behavior — in predicting ultra-processed food (UPF) consumption among university students is Saudi Arabia.

Methods: A cross-sectional design was employed, involving 384 students enrolled at Northern Border University (NBU). Data were collected through a validated questionnaire that assessed socio-demographic characteristics, UPF-related knowledge, TPB factors, and self-reported UPF consumption. Participants were stratified into low, moderate, and high knowledge groups for comparative analysis.

Results: Significant associations were observed between UPF knowledge and sex, marital status, and academic discipline. Higher knowledge levels were correlated with less favorable attitudes toward the safety of UPFs and heightened susceptibility to social influence. Structural Equation Modelling (SEM) revealed that, across the overall sample, attitudes significantly predicted behavioral intention (β = 0.59, p < 0.001), whereas perceived behavioral control (PBC) exerted a negative effect on behavior (β = –0.22, p < 0.001). Notably, among participants with high-knowledge, neither intention (p = 0.884) nor PBC (p = 0.453) significantly predicted UPF consumption, and the model accounted for a negligible proportion of variance in behavior (R² = 0.01), indicating a pronounced intention–behavior discrepancy within this group.

Conclusions: Among NBU students, nutrition knowledge regulates psychosocial determinants of UPF consumption but appears to weaken the intention–behavior connection. These findings suggest that effective interventions should extend beyond educational initiatives to incorporate habit-formation strategies and environmental modifications that support sustained dietary behavioral modification.