Social Media, Health Consciousness, and Cultural Influences on Sugar Reduction Behaviors in Chinese Youth: Extending the Stimulus-Organism-Response Model.

Background: The rising prevalence of sugar-related diseases, such as obesity and diabetes, has intensified efforts to reduce sugar intake, particularly among youth. In China, social media is playing an increasingly significant role in shaping health behaviors, including habits related to sugar consumption, as sugar reduction has become a prominent youth-led movement. Objective: This study extends the stimulus-organism-response (SOR) model by incorporating the distinct cultural influence of "face" to investigate the impact of social media on sugar reduction behaviors (SRBs) among Chinese youth, as well as the mediating role of health consciousness (HC) and conformity, and the moderating effects of face concern (FC) and eHealth literacy (EHL). Methods: We conducted a national web-based, cross-sectional survey through proportionate probability sampling of 883 Chinese youth in July 2024. Descriptive statistics, Pearson correlations, model fit indices, and partial least squares. Structural equation models were used to examine the relationships among all variables. Results: Nearly half of the 883 participants were female (460/883, 52.1%), 91.9% (812/883) were aged 15-30 years. Most participants (602/883, 68.2%) had undergraduate education levels; the majority (688/883, 77.9%) had a bachelor's degree or higher, and 654 (74.1%) had a normal BMI. Most participants (575/883, 74.1%) had used social media for 3-10 years. Chinese youth reported relatively high SRB scores (mean 3.62, SD 0.99). Male participants achieved notably higher scores (mean 3.72, SD 0.93), whereas participants aged 15-18 years showed significantly lower SRB scores (mean 3.50, SD 1.05). Structural equation modeling revealed that social media usage positively influenced conformity (β=.51; P<.001) and HC (β=.35; P<.001). These factors, in turn, significantly predicted SRBs (β=.14 and β=.50, respectively; both P<.001). The influence of social media usage on SRBs is primarily facilitated through 2 mediating pathways: HC mediated the relationship (Variance Accounted For=51.5%), while conformity's mediation was less pronounced (Variance Accounted For=21.05%), indicating a secondary influence. FC (β=.09; P=.02) and EHL (β=.06; P=.04) moderated the respective relationships. Conclusions: This study demonstrates that social media effectively promotes SRBs among Chinese youth. By embedding cultural influences, such as FC, alongside enabling competencies, such as EHL, in an extended SOR model, we enhance our understanding of social media's influence on health behaviors. The findings highlight cultural nuances in health communication and position the enhanced SOR model as a framework for health promotion. Furthermore, the study underscores the primary mediating effect of HC-surpassing that of conformity-while also delineating the moderating roles of FC and EHL, offering actionable insights for digital-age public health strategies.