FitBit fun

I have had my FitBit for a few days now, and I am having far too much fun with it. I have even been logging my food, which was not my intention when I bought it. I don't quite understand the thinking behind the calorie counting anyway. I always though that you were supposed to have a set calorie count that you were aiming for, like 2000, and that was it. FitBit gives you more and more calories the more you eat, even though I am on the "hardest" eating plan. What good is it if I do good exercise but then feel justified to go eat 1000 more calories? This is what the eating plan suggests. Somebody help me out here. I am not normally a calorie counter in the first place simply because I find it to be too simplistic.

I love tracking my steps though, and distance, and all the other cool stuff. I am sure I will lose interest in it eventually but for now it is fun.