>R U saying that the insulin could rise after the four-hour period?

I think it's possible. Why not? I guess it depends on whether you believe
that fat can cause a rise in insulin levels. I recall at least one study
that says it can. Utilization of blood lipids is at least partially
controlled by insulin levels.

Here's a very interesting article which looked at insulin and glucose from
three meals (of varying composition) over a 1000-minute period (16 hours).
I haven't printed it out for study, but at a glance it appears that fat
does affect insulin levels and that the insulin response to high fat meals
is delayed by several hours. Of great interest to me is that the responses
for men and women in this study were quite different.

Full text and graphics at
http://jap.physiology.org/cgi/content/full/85/3/935