Calorie Deficit question

I have never used a Fit bit, but I use body media....I know that the body media will calculate "off body" calories burned based on how long I forgot to wear it and what my normal at rest calorie burn is...so it was probably just doing that when it told you that you had burned 900 calories. You should try linking your fit bit to MFP....I have my body media linked and it automatically adds the extra exercise calories I earn.

Also, I took a nutrition class a while ago, and the nutritionist recommended NOT EATING your exercise calories, unless you're ridiculously super active. It will make your weight loss go a little more quickly.