Elevated postprandial insulin levels do not induce satiety in normal-weight humans.
To determine whether an elevated insulin level contributes to satiety, two experiments were conducted using a covert system of monitoring food intake. Normal-weight volunteers received intravenous infusion of either 0.15 M saline or a mixture of glucose and insulin during a single-course meal. In the first group, the glucose-insulin infusion (0.03 U insulin X kg-1 X h-1 and 0.25 g glucose X kg-1 X h-1) was begun 30 min before the start of the test meal and ended 15 min after subjects had voluntarily stopped eating. Plasma insulin was raised threefold, and glucose increased 20 mg/dl above preinfusion base line at time of eating. In the second group, the glucose-insulin mixture (insulin bolus of 12 mU/kg plus 0.03 U insulin X kg-1 X h-1 and 0.125 g glucose X kg-1 X h-1) was delivered 12 min after an appetizer was served and just as the test meal began. This infusion was stopped 12 min after the end of the meal. Serum insulin was fourfold higher than saline infusion levels at onset of eating, but glucose remained the same. The changes induced in these studies by the glucose-insulin infusions mimicked normal insulin and glucose levels seen shortly before satiation is complete in a meal. No effect on meal size or duration was observed. Therefore normal postprandial elevation of insulin is unlikely to signal satiety in humans.
D004435:Eating; D005260:Female; D005947:Glucose; D006801:Humans; D007328:Insulin / Q000097:blood*; D008297:Male; D012527:Satiation; D013997:Time Factors
D007328:Insulin; D005947:Glucose