J Clin Endocrinol Metab 1988 Feb;66(2):323-326

The acute effect of fat on insulin secretion.

Collier GR, Greenberg GR, Wolever TM, Jenkins DJ

Previous studies suggest that the rate of rise of the plasma glucose-dependent
insulinotropic peptide (GIP) concentration, rather than the steady state level
achieved, may be the stimulus of the increased insulin secretion that occurs
when fat is ingested with carbohydrate. To test this hypothesis six normal men
were given a 5-g iv bolus dose of glucose 15 min after a carbohydrate meal with
or without fat. At the time of the iv glucose injection after the fat-containing
meal, the rate of rise of plasma GIP was maximum, but the level was only 40% of
the achieved by 30 min. Plasma GIP did not change after the meal without fat.
After the fat meal, peak insulin and C-peptide levels in response to iv glucose
were 60% greater than those after carbohydrate alone despite similar peak blood
glucose levels. The calculated insulin clearance was not altered by the fat
meal. We conclude that glucose-stimulated insulin secretion is increased early
after fat ingestion, possibly due to a rise in GIP or other incretins.

PMID: 3276722, UI: 88115822