Gestational diabetes mellitus (GDM) is a common metabolic disorder of pregnancy characterized by glucose intolerance that arises during gestation. Its prevalence is increasing globally, with significant implications for both maternal and neonatal health. This narrative review explores the pathophysiology, maternal and fetal risks, and particularly the central role of nutrition in the prevention and management of GDM. Gestational diabetes mellitus, nutrition, medical nutrition therapy, glycemic index, pregnancy outcomes, maternal health.