Early insulin and glucagon responses to different food items.

An early postprandial insulin release has previously been described when high carbohydrate meals are fed. The present investigation on humans shows that this response takes place not only with high carbohydrate (sugar pie) but also with high lipid (whipped cream) and protein (beef steak or fish fillet) meals, suggesting that it is caused by the palatability of the food rather than to its composition. This increment takes place at the very beginning of the meal and even if the period of feeding lasted 10 min, the response has disappeared at that time. Thirty min later due to plasma glucose elevation, a significant increase in insulin was observed with the sugar pie. At that time a similar increase was observed with the fish filet or the beef steak but not with the whipped cream. A cephalic glucagon response was not observed with any of the meals but 30 min after feeding the plasma level of this hormone increased with both beef and fish feeding and decreased significantly with the sugar pie meal. The usefulness of these responses is discussed with relation to the metabolic responses associated with feeding.