It depends on the oats -- or rather how they oats were processed.

Steel cut oats are have a lower glycemic index than rolled oats which
have a lower glycemic index than instant oats (which are thinly sliced
rolled oats).  Of course, it also depends on if you sweetened your
oatmeal with anything, etc.

Was it oatmeal with milk or water? What kind of milk? How much oatmeal
did you eat?Could it be that you simply did not eat all that much and
that caused your hunger? What kind of oatmeal was it, some instant
stuff or rolled oats?

instant oats, 87 (same as ice cream)
slow cooking oats, 70.

If you think that your blood sugars misbehave in response to some
food, the best thing to do is to buy a blood glucose monitor and check
yourself a few times. These monitors can be bought very cheaply at
walmart.

Also, for me, when I fast, my hungr is relatively subdued, until Istart
eating. Then it wakes up.

i

http://diabetes.about.com/library/mendosagi/ngilists.htm

Steve

I don't find the glycemic index useful at all as it does not examine
the digestibility of carbs, just the insulin spike.

WHEN you eat counts almost as much as WHAT you eat.  You just learned
why mothers refuse to allow a child to go to school without eating
breakfast first, and you learned it still applies to adults.

For the same total calories across the day, it is very easy to be
more or less hungry depending on when you eat your foods.  This is
why folks push having breakfast, why folks push having several
small meals instead of big ones, and so on.

Alternate speculation - When you regularly eat breakfast, you are
not yet hungry, right?  It that's right then you're eating your
breakfast to *prevent* hunger.  Instead today you ate it to *cure*
hunger.  "An ounce of prevention is worth a pound of cure."  I
suspect that if you never allow yourself to get hungry, you can
end up eating less food total across the day.  But allow yourself
to get hungry and it takes more to stop it than it took to prevent
it.