You'll get the calorie adjustment based on differences between Fitbit and estimated MFP calorie burns.
http://community.myfitnesspal.com/en/discussion/10098937/faq-syncing-logging-food-exercise-calorie-a...
"Why doesn't my MFP Exercise Diary - Fitbit calorie adjustment equal my workout calorie burn?
Because that MFP figure is not exercise.
That figure is the difference between Fitbit's total daily burn which includes your exercise, and what MFP thought you'd burn with no exercise.
Any difference includes exercise and daily activities. You could have no exercise and big positive adjustment from being very active. You could have big exercise and no positive adjustment from being very inactive that day outside of exercise.
You can see this fact by clicking on the "i" for more info on that Fitbit calorie adjustment line.
You should enable Negative Calorie adjustment too for sick or lazy days.
MFP - Settings - Diary Settings - Calorie Adjustments - Enable Negative Adjustments.
The reason it's put under exercise is so MFP correctly increases your eating goal, so the same deficit is maintained. You do more, you eat more, same deficit. MFP is merely correcting it's estimate of daily burn, which is based on your selection of activity level, and if you selected wrong, you get big adjustments, and then deficit is taken."
