Cravings for desert

If you're eating a lot of carb in your meals, it's possible that you're experiencing what some books call a "glycemic reaction" or "insulin reaction". This is where (for some people --- approx %60 or so they say), don't metabolize carb's efficiently, so when you a meal, even a small one, that is high in carbs - the following reaction occurs.
Since this kind of person doesn't metabolize carbs very well, instead of converting the carbs to energy, they get converted into body fat (which is much easier for the body to do for some peope). So, even though you JUST ATE, you're still feel VERY HUNGRY & have craving because you really didn't get any energy from your from your meal.
I definitely notice this effect personally. If I eat a bowl of rice or pasta (which has a lot of calories & carbs) - I will almost immediately get tired/sleepy (while the body is converting it body fat) and then I will hungry again in just 1-2 hours since I didn't get any good energy from the meal. This is true (for me) even if I eat a very large bowl of rice or pasta.
BTW - The discovery of this effect is what has led to the "Low - Carb Diet" craze. Of course they went completely overboard with it, but the underlying principle is sound. It varies from person to person, but if you get immediately tired & then hungry about 1-2 hours later (after a high-carb) meal, then you're probably one of the people that has this "glycemic reaction". There are several good books that describe this much better.