The association between orthorexia nervosa and social media use: A systematic review and meta-analysis.

Orthorexia nervosa (ON) is a newly described mental disorder characterized by an extreme obsession with the consumption of healthy foods, resulting in anxiety and impaired functionality. This systematic review and meta-analysis aims to synthesize the association between social media use and orthorexic tendencies among adolescents and adults. PubMed, Web of Science, Embase, Scopus, and PsycINFO were searched through January 2026. Original studies assessing the association between social media use and ON were included. Zero-order correlations between social media and orthorexia measures were pooled using Fisher's z under a random-effects (REML) model; heterogeneity, subgroup and meta-regression, sensitivity and publication-bias analyses were performed; certainty was rated with GRADE. Of 33 included studies, 22 contributed to meta-analysis of the correlation between social media use and ON symptoms, yielding a small positive pooled correlation (r = 0.20, 95% CI 0.15-0.25; I² = 84.3%; very low certainty by GRADE). This association remained stable across leave-one-out, subgroup, and sensitivity analyses (r = 0.18-0.20), and after adjustment for potential publication bias (bias-adjusted r = 0.17). A secondary analysis of two studies with reconstructable 2 × 2 data suggested greater odds of ON among heavier users (OR = 1.57, 95% CI 1.25-1.97). Pooled ON prevalence differed sharply with the diagnostic threshold (39.9% at the ORTO-15 cutoff below 35 versus 65.5% below 40), reflecting extreme heterogeneity (I² > 90%) across studies. Narrative synthesis indicated that the type of content consumed was more consistently associated with ON than platform or duration of use alone Social media use is associated with greater orthorexic tendencies. However, because all included studies were cross-sectional and overall certainty of evidence was very low, causality and directionality cannot be established and reverse causality remains plausible. Longitudinal and experimental research is needed to clarify the direction of this relationship.