You said that you have gradually been increasing your exercise. You could try stabilizing it for a couple of weeks -- stay at the same level you are now -- and see what that does to your appetite. Whenever I increase the intensity of my exercise, I notice that I get much hungrier. After I get used to the new level, my hunger goes down. I think that what is happening is that I am physically tired when I am pushing myself more and our bodies often confuse tiredness and hunger. I know that the same thing happens when I don't get enough sleep -- I am famished the next day.