Conventional dietary recommendation for obesity management is a low-fat energy-restricted diet, which however, only have modest and non-sustained effects on weight reduction. Alternative dietary interventions, including low-glycemic index (GI) diet, have been proposed.
Glycemic index is a measure of blood glucose excursion per unit of carbohydrate. Foods with high GI are rapidly digested, absorbed and transformed into glucose. These processes cause accelerated and transient surges in blood glucose and insulin, earlier return of hunger sensation and excessive caloric intake. Conversely, low-GI diet decreases blood glucose and insulin excursion, promotes greater fat oxidation, decreases lipogenesis and increases satiety. Modern food-processing technology has produced many food products with high GI which may contribute to the burgeoning epidemic of obesity especially in children/adolescents.
Epidemiological and clinical trials suggest a role for low-GI diet in the management of childhood obesity and associated cardio-metabolic risks although results are not always consistent. In this article, we shall review the physiological basis and current evidence for and against low-GI diet in obesity management, with particular focus in children and adolescents.