I used to get this...it was usually because I was going to bed hungry, and my body couldn't stand it any longer.

Is it habit? You might have used carbs sedative effects in the past, and now are in the habit of using it to get that drowsy feeling.

Are you going to bed hungry? Eating at six and going to bed at midnight is a six hour span--no wonder!

Have you tried supplements like L-Glutamine or Conjugated Linoleic Acid (CLA) or any of the others that are talked about here to fight cravings? Hungry is a real feeling, might be stemming from a lack your body has.