Secretion and removal of insulin by diet

The effect of a carbohydrate (C) and a carbohydrate-fat (CF) meal on peripheral plasma insulin and C-peptide levels was studied in seven healthy female volunteers. Lower but prolonged elevation of both hormones was observed after the CF meal. The C-peptide:insulin molar ratio was decreased profoundly at 30 and 60 min after each meal. After the C meal it returned to normal within 120 min but then was increased above the basal value at 180 min. After the CF meal the reduction in the C-peptide:insulin molar ratio persisted until 180 min after food intake and then the ratio increased above the level at 240 min. It is concluded that both meals increase the peripheral insulin level in two ways: increasing secretion and decreasing removal of the hormone. At the end of digestion, the latter effect is reversed and increased insulin removal seems to occur.