Ghrelin is a peptide hormone that plays a central role in short-term appetite regulation and energy balance. Its secretion is not only influenced by nutritional status but also shaped by circadian rhythms and habitual eating patterns. Ghrelin levels typically rise during fasting and decrease after meals, but they also follow a daily rhythm, peaking during the night and reaching their lowest levels in the morning. Human studies suggest that consistent meal schedules may entrain ghrelin secretion, with anticipatory rises occurring before habitual mealtimes. Experimental interventions show that morning-loaded eating patterns, compared to evening-loaded ones, lead to stronger postprandial ghrelin suppression, enhanced satiety hormone responses, and greater weight loss, even with similar caloric intake. In contrast, delayed or misaligned eating, such as during night-shift work, is associated with elevated ghrelin levels at biologically inappropriate times and increased hunger. Some studies have also highlighted the leptin-to-ghrelin ratio as a useful marker of appetite regulation and metabolic risk, particularly in overweight individuals. Together, these findings support the idea that the timing of food intake modulates ghrelin dynamics and influences metabolic outcomes. Meal timing, when aligned with endogenous biological rhythms, may therefore serve as a practical target for chrononutritional strategies aimed at improving appetite control and weight regulation.
Circadian Biology