Fasting and postprandial total ghrelin remain unchanged after short-term energy restriction

Adaptations that promote positive energy balance appear in response to dietary restriction. The aim of this study was to determine whether fasting and postprandial total ghrelin increase in response to short-term energy restriction. Fifteen adult male subjects were subjected to a 4-d energy restricted diet (-800 kcal/d). Body weight and composition, resting energy expenditure, respiratory quotient, fasting and postprandial appetite scores, and fasting and postprandial serum leptin and total ghrelin were determined before and after dietary intervention. Despite the fact that fat mass remained unchanged after the 4 d, fasting (-36%; P less than or equal to 0.01) and postprandial serum leptin (-27%; P = 0.01) were significantly reduced. A significant reduction in total ghrelin was observed after the meal (P less than or equal to 0.05); however, fasting and postprandial total ghrelin remained unchanged at the end of the intervention. Although leptin was a significant correlate of appetite before and after the intervention, no such associations were noted for total ghrelin. Finally, a significant relation between total ghrelin and respiratory quotient was noted at the onset of the diet (r = 0.63; P less than or equal to 0.01). Fasting and postprandial total ghrelin levels remain unchanged after short-term energy restriction despite a significant fall in leptin.