Social Media Exposure and Dietary Quality in University Restaurant Consumers: A PLS-SEM Approach from Northern Peru

University students face dietary transitions shaped by time constraints, campus food environments, and intensive exposure to food-related content on social media, yet the mechanisms linking digital exposure to observable food choices and overall diet quali-ty remain insufficiently modeled in Latin American contexts. This study examined whether social-media-driven food norms (NI) and in-restaurant food choices (CD) se-quentially mediate the effect of Instagram (IG) and TikTok (TK) exposure on overall diet quality (Y), while incorporating physical activity (PA) as an independent predic-tor. A cross-sectional survey was administered to 615 university students consuming in campus restaurants in La Libertad, Northern Peru. Data were analyzed through PLS-SEM (SmartPLS 4) with 5,000 bootstrap resamples and BCa 95% confidence in-tervals; Y was operationalized through a culturally adapted KIDMED index. All five structural hypotheses were supported: TK → NI (β = 0.479) exceeded IG → NI (β = 0.349); NI → CD (β = 0.473) and PA → CD (β = 0.216) operated as independent path-ways; and CD → Y (β = 0.255) confirmed the distal link. NI fully mediated both digital pathways toward food choices. Diet quality in university restaurants is reconfigured primarily through normative, not informational, digital mechanisms, suggesting norm-based interventions over nutrition-information campaigns.