The relationship between diet and sleep is more specific and actionable than general wellness advice typically captures. The foods consumed in the three to four hours before sleep affect sleep onset time, the quality of deep sleep stages, and waking frequency in measurable ways.
What Helps Sleep
Tryptophan is an amino acid that serves as a precursor to serotonin and melatonin, both of which regulate sleep. Foods high in tryptophan include turkey, eggs, cheese, nuts, and seeds. Consuming tryptophan-rich foods alongside a small amount of carbohydrate improves tryptophan's transport across the blood-brain barrier, which explains the drowsiness often attributed to turkey at holiday meals.
Magnesium, which is involved in GABA function and muscle relaxation, is consistently associated with sleep quality. Foods high in magnesium include dark leafy greens, pumpkin seeds, dark chocolate, and legumes. Magnesium glycinate supplementation in the evening has good evidence for improving sleep quality in deficient individuals.
What Disrupts Sleep
Alcohol is the most common sleep disruptor in the category of things people consume as sleep aids. While alcohol sedates initially, it suppresses REM sleep and causes waking in the second half of the night as it is metabolized. The consequence is lighter, more fragmented sleep despite the earlier feeling of relaxed sedation.
High-glycemic foods consumed in the hours before sleep cause blood glucose to rise and fall, triggering cortisol release that can cause waking in the early morning hours. Stable blood glucose through the evening, achieved by avoiding refined carbohydrates and sugar after dinner, produces longer uninterrupted sleep in many people.
