The Effects of Food on Circadian Rhythm: A Comprehensive Review

Circadian rhythms regulate essential physiological functions such as metabolism, hormone secretion, and sleep–wake cycles. While light entrains the central clock in the suprachiasmatic nucleus (SCN), food serves as a powerful zeitgeber (an external environmental cue that synchronizes biological rhythms) for peripheral clocks, especially in metabolic tissues. Disruptions in meal timing, composition, or regularity can desynchronize these clocks and contribute to metabolic disorders. This review synthesizes current evidence on how dietary factors influence circadian regulation. We describe key nutrient-sensing pathways (AMPK, mTOR, SIRT1) and their role in clock gene modulation. The effects of macronutrients, micronutrients, and specific components—including fiber, phytochemicals, caffeine, and alcohol—on circadian physiology are examined in detail. We also explore the impact of meal timing strategies such as time-restricted feeding and discuss dietary considerations for shift workers and other at-risk populations. By integrating mechanistic insights with evidence-based dietary recommendations—such as optimal meal timing, macronutrient distribution, and nutrient-specific strategies, this review highlights the role of diet as a modifiable factor for circadian health. Aligning food intake with endogenous rhythms offers a promising strategy for improving metabolic outcomes and preventing circadian disruption in modern lifestyles.