Fitbit calories for the day don't equal mfp calories for the day?

Hello all! I'd like to go by the calories Fitbit says I have left instead of mfp. I still log my food in mfp though. I have my accounts synced so that my Fitbit account adds or subtracts calories from mfp based on my activity level. How should I configure my mfp account to have the calories that Fitbit says I have left for the day be the same as what mfp says I have left for the day? I currently have mfp set to -2 lbs/week and sedentary, but if I eat what mfp says I can eat after my Fitbit calories are added in I do not lose since it is much higher than what Fitbit says I should eat. Thanks for any help you guys can give me!