Delayed sleep phase is a circadian rhythm condition characterized by a persistent shift of the body’s biological clock toward later evening alertness and later morning wakefulness. Individuals commonly experience difficulty falling asleep at conventional times, delayed melatonin secretion, reduced morning alertness, late-night energy surges, impaired morning concentration, irregular appetite timing, and altered sleep architecture. The circadian system is regulated primarily by the suprachiasmatic nucleus within the hypothalamus, which synchronizes hormone release, body temperature, neurotransmitter activity, feeding behavior, metabolic timing, and sleep-wake cycles in response to environmental light and behavioral timing cues. Exposure to bright artificial light during late evening hours may suppress melatonin signaling and delay circadian timing further. Irregular meal schedules, excessive evening caloric intake, refined sugar exposure at night, chronic stress signaling, elevated evening cortisol, nighttime screen exposure, inconsistent wake times, and reduced morning sunlight exposure may all contribute to circadian dysregulation. The serotonin-melatonin pathway plays an important role because serotonin synthesized from tryptophan serves as a precursor for melatonin production in the pineal gland. Mitochondrial energy metabolism, oxidative stress regulation, inflammatory signaling balance, and glucose stability are also closely linked to circadian rhythm regulation. A whole food plant-based dietary pattern emphasizing stable blood sugar regulation, magnesium-rich foods, potassium-containing fruits and vegetables, antioxidant-rich plants, high-fiber whole foods, and polyphenol-rich evening nutrition patterns may help support circadian signaling and nervous system recovery. Foods rich in tryptophan, vitamin B6, magnesium, folate, and antioxidant phytochemicals may support neurotransmitter balance and normal melatonin-related biological timing systems. Consistent meal timing and minimizing heavy late-night processed food intake may also support healthier circadian entrainment. Kiwi, oats, tart polyphenol-containing berries, pumpkin seeds, chickpeas, bananas, leafy greens, walnuts, green tea earlier in the day, and magnesium-rich legumes provide compounds associated with nervous system regulation, oxidative stress defense, glucose stability, neurotransmitter synthesis, and circadian biology support. Polyphenols including quercetin, catechins, anthocyanins, chlorogenic acid, and EGCG may help support oxidative balance within neural tissues involved in circadian timing. Fiber-rich whole foods may additionally support gut microbiome activity and short-chain fatty acid production associated with circadian metabolic synchronization. Proper hydration, stable evening meal composition, reduced processed food exposure, and consistent nutrient-dense whole plant food intake may help support biological rhythm stability and sleep timing regulation.