Deleting my Fitbit exercise calories?

Fitbit syncs with MFP every time you sync your Fitbit with your app (or computer). The number you see is based on what you've done so far (measured by your Fitbit) versus what MFP calculates you should have done so far (based on the settings you gave it, so sedentary, lightly active, etc.) If you exercise early in the day but then sit around the rest of the day, what will happen is just what you described. You'll see calories early on (reflecting your higher than expected burn), and then as the day goes on, they go away (reflecting that even though it had calculated you were going to end up ahead, by the time midnight hit, your calorie burn for the day was just at MFP's original estimate). If it says your Fitbit adjustment is zero (0), that's what happened. Unfortunately, you need to move more than you've been moving to burn extra calories.

If you don't have negative calorie adjustments turned on (on MFP), it could actually even be that you burned _less_ than what MFP calculated you were going to. If that's happening, it will still show zero until you turn on negative adjustments.

Good luck!