Evening chronotype as a predictor of eating disorders: a systematic review and meta-analysis

Introduction

The circadian clock is an endogenous biological system synchronized with the 24-hour day–night cycle that regulates sleep–wake rhythms, hormonal secretion, appetite, and behavior. Individual differences in circadian timing are characterized by chronotype, which spans a continuum from morning to evening preference. Evening chronotype has been associated with circadian misalignment, disrupted hormonal regulation, impaired impulse control, maladaptive eating patterns, and elevated somatic and psychological pathology. Eating disorders are severe psychiatric conditions with rising prevalence and considerable medical and psychological morbidity. Their multifactorial etiology encompasses biological, psychological, and environmental contributors, with the circadian rhythm dimension remaining underexplored. Several biological, psychological and behavioral processes may link evening chronotype to disordered eating. Evening-type individuals share personality characteristics with eating disorder patients including impulsivity, neuroticism, and perfectionism that heighten vulnerability to maladaptive eating behaviors. Dysregulated secretion of appetite-related hormones (cortisol, ghrelin, leptin, and melatonin) amplifies nocturnal hunger. Orexin activity during extended wakefulness promotes food-seeking behavior; and late eating patterns may function as a zeitgeber, reinforcing a self-perpetuating cycle of circadian delay and nocturnal binge eating. Although accumulating evidence links evening chronotype to various forms of psychopathology, the specific association between evening chronotype and eating disorders lacks a comprehensive quantitative synthesis.

Aims

The present study aimed to examine the association between circadian chronotype and eating disorders through a systematic review and meta-analysis of available studies.

Methods

This study was conducted in accordance with the PRISMA guidelines. A systematic literature search was performed using the PubMed and Google Scholar databases and included studies published up to September 2025. Studies were eligible if they: (a) were written in English; (b) included a validated measure of chronotype; (c) assessed eating disorder symptoms or diagnosis; and (d) reported the association between chronotype and eating disorders. Eating disorder status was determined via validated self-report questionnaires in 13 studies and via formal clinical diagnosis in one study. A random-effects meta-analytic model was applied using inverse-variance weighting. Publication bias was evaluated via funnel plot inspection and Egger’s regression test.

Results

Following systematic screening, 14 studies met all inclusion criteria, encompassing a total of 5,436 participants. The pooled effect demonstrated a statistically significant association between chronotype and eating disorders (Fisher’s Z = −0.17, 95% CI [−0.23, −0.12], p < .0001), such that individuals with an evening chronotype exhibited a higher prevalence of eating disorder symptoms relative to morning type individuals. Substantial heterogeneity was observed (τ² = 0.0073, I² = 72.87%). Egger’s regression test indicated no significant publication bias (z = −0.788, p = .431).

Conclusions

The present meta-analysis provides strong quantitative support for the significant association of evening chronotype with eating disorders across diverse populations and measurement approaches. These findings suggest that circadian factors warrant greater attention in etiological models and clinical frameworks for eating disorders. Future longitudinal and experimental research should explore the development of chronotype-sensitive clinical interventions.

References

No references