Fitbit

The Fitbit will give you positive Calorie adjustments if your actual daily activity is greater than the estimated daily activity you chose when you picked your MFP Activity Level when setting your MFP goals. If you chose Very Active in MFP, but only take enough steps for a Sedentary setting, you will not get a positive Fitbit Calorie adjustment based on your actual steps as recorded by Fitbit. Or, in reverse, if you chose MFP Sedentary, and then take thousands of steps beyond the Sedentary MFP Activity Level setting, you will get a rather large Fitbit Calorie adjustment.

​I would recommend reading through the first three posts in this thread on the MFP Fitbit Users group...

http://community.myfitnesspal.com/en/discussion/10098937/faq-syncing-logging-food-exercise-calorie-adjustments-activity-levels-accuracy

http://community.myfitnesspal.com/en/group/1290-fitbit-users​