I also use cinnamon in my breakfast, especially if I am having oats as I find it very delicious. There is a large body of research backing up the theory that cinnamon regulates blood sugar and can even play an active role in combating diabetes.
I would like to add the micro-nutrient, Chromium, here. I have read about it in many books and heard about it at talks. Apparently, Chromium as a supplement plays a huge role in balancing blood sugar and you can tell if you are lacking in it if you tend to get a craving for something sweet after a meal. This is what food guru. Patrick Holford says.
Also, according to statistics, almost all overweight people are lacking chromium. I have not supplemented with chromium but I DO faithfully take my cinnamon. I will try chromium some time in the future...