Physiological and Nutritional Observations in Healthy People During Ramadan Fasting

Abstract Ramadan fasting (RF) is a globally practiced, month-long religious fast characterized by complete abstinence from food and fluid intake from dawn to sunset. Unlike secular intermittent fasting, RF occurs within a structured behavioral and cultural framework that shapes metabolic and physiological adaptation. RF induces coordinated metabolic adaptations, including increased lipid oxidation and preservation of glucose homeostasis, with generally neutral to favorable effects on cardiometabolic risk markers. Circadian and hormonal changes reflect adaptive realignment to nocturnal feeding patterns rather than dysfunction. Nutritional quality, hydration, and behavioral factors during non-fasting hours emerge as primary determinants of health outcomes. RF represents a model of integrated metabolic and behavioral adaptation in which outcomes are driven by dietary quality, hydration, and sustained lifestyle behaviors beyond Ramadan.