Applying self-determination theory to internalized weight stigma and mental health correlates among young and middle adult women: A structural equation model.

Limited research has explored the relationship between self-determination theory constructs (basic psychological needs, autonomous/controlled regulation) and internalized weight stigma (IWS). This cross-sectional, online study surveyed 480 U.S. women aged 18-40 between 2021 and 2022. We hypothesized that need frustration and controlled weight regulation would relate to higher IWS, which would be associated with dysfunctional eating, distress, and lower life satisfaction. Conversely, we predicted that need satisfaction, autonomous regulation, and body satisfaction would be associated with reduced IWS, dysfunctional eating and distress, and higher life satisfaction. Structural equation modeling demonstrated an acceptable model fit (CMIN/DF = 2.95, CFI = 0.90, RMSEA = 0.06, SRMR = 0.07), accounting for 74% of IWS variance. Findings indicate the relevance of self-determination theory in understanding IWS, supporting a dual-process model whereby adverse and adaptive outcomes follow distinct pathways. Longitudinal studies are warranted to validate psychological needs and regulatory styles as mechanisms for IWS development and to assess generalizability across diverse populations.