Dietary self-regulation levels among adults in Shanghai: cross-sectional associations with e-health literacy, perceived stress, and rest intolerance

Background Dietary self-regulation supports healthy eating, but its cross-sectional associations with e-health literacy, perceived stress, and rest intolerance remain unclear. This study characterized dietary self-regulation levels among adults in Shanghai and estimated direct and indirect associations among these variables. Methods A cross-sectional survey of 1,011 permanent adult residents of Shanghai was conducted from July to September 2024. Validated questionnaires assessed e-health literacy, dietary self-regulation, perceived stress, and rest intolerance. Associations were examined using Spearman correlations, exploratory latent profile analysis, and a prespecified serial indirect-association model (PROCESS Model 6; 5,000 bootstrap resamples) adjusted for gender, age, education, employment, residence, and income. Results The selected three-class solution primarily distinguished low, moderate, and high overall dietary self-regulation, with largely parallel item-response patterns rather than qualitatively distinct subtypes. E-health literacy was positively associated with dietary self-regulation and rest intolerance and negatively associated with perceived stress; perceived stress was negatively associated with dietary self-regulation, whereas rest intolerance was positively associated with it. The total association between e-health literacy and dietary self-regulation was 0.615 (95% CI, 0.564–0.666); the association conditional on perceived stress and rest intolerance was 0.211 (95% CI, 0.147–0.274), and the total indirect association was 0.404 (95% CI, 0.344–0.466). The serial indirect association was small and negative (−0.015; 95% CI, −0.031 to −0.001), and the perceived stress-rest intolerance coefficient reversed direction after adjustment. Conclusion The variables were interrelated in the prespecified cross-sectional model, but the small serial estimate and directional instability do not support a clear sequential psychological mechanism. Because all variables were measured at one time point, temporal ordering and causal mediation cannot be established, and reverse causality remains possible. These findings are hypothesis-generating and require longitudinal or experimental confirmation.