Increasing the calorie content of meals in normal weight subjects progressively lowered nadir levels of ghrelin. The obese had lower fasting ghrelin levels and the reduction following the consumption of all test meals was less than the normal weight subjects. The lowest postprandial levels in the obese were no different to the nadir in normal weight volunteers following 1000, 2000 and 3000 kcal meals. Circulating ghrelin levels thus decreased in normal weight subjects following mixed meals. Obese subjects demonstrated a much reduced ghrelin postprandial suppression. This reduced suppression may influence satiety thus reinforcing obesity.