Chrono-Nutritional Disruption as a Potential Modifiable Factor in Bipolar Disorder

Bipolar disorder is characterized by marked circadian and metabolic vulnerability, but direct evidence linking the timing of food intake to its course remains sparse. This structured narrative review examines chrono-nutritional disruption, including irregular meal timing, nocturnal eating, prolonged or inconsistent fasting, eating-window variability, and eating jet lag, as a potential behavioral correlate and mechanistic contributor to bipolar instability. PubMed/MEDLINE, Scopus, and Web of Science were searched for literature published from January 2000 to 30 June 2026, supplemented by predefined foundational studies. Evidence was organized as direct bipolar-specific, indirect human, or translational/preclinical. The strongest direct findings are cross-sectional associations involving night eating, eveningness, sleep disturbance, and functioning; bipolar-specific longitudinal and completed interventional evidence remains insufficient. Indirect human and experimental studies suggest that biologically mistimed eating can alter peripheral-clock entrainment, glucose-insulin regulation, cortisol rhythmicity, mitochondrial function, inflammatory signaling, and gut microbial rhythms. On this basis, we propose a hypothesis-generating chrono-metabolic model in which food timing may interact bidirectionally with sleep, mood state, medication effects, and metabolic health. Routine attention to nutritionally adequate and feasible meal regularity may be considered within broader monitoring of social rhythms, but it has not been shown independently to prevent relapse or improve mood outcomes. Time-restricted eating is investigational in bipolar disorder and should be evaluated only in carefully monitored research or specialist contexts. Prospective within-person studies and adequately powered trials are required before chrono-nutritional strategies can be regarded as evidence-based bipolar interventions.