Negative Adjustment

newNRGkate

I just got my Fitbit Flex this past weekend so I'm just getting started learning. I have been using MFP to log my food and exercise off and on over the years but was excited to get my Fitbit to get a more accurate calorie burn. I was equally excited that Fitbit syncs with MFP.
I totally do not understand the negative adjustment. For instance, this day I did zumba which on MFP says I burned 519 calories but it then gets subtracted by my Fitbit so my calories for the day stayed at 1200 and didn't adjust for my activity.
Can someone explain in simple terms how this works? Should I be logging zumba and walking or not? How do the calories burned which show on my Fitbit dashboard translate/show up in MFP?

heybales

Fitbit calories show up on MFP because they sync across. But you don't actually see the totals, you see the difference between what MFP estimated by your profile setting options, and what Fitbit thinks you burned.

Since I don't know how much of the whole thing you understand, I'll just tell a little story.

Profile at Sedentary (whether true or not), weight loss at 2 lbs weekly (reasonable or likely not). BMR 1600.
1600 x 1.25 sedentary factor = 2000 estimated daily maintenance with no exercise included.
2000 - 1000 cal deficit = 1200 (because MFP stops at 1200) eating goal on non-exercise days. Or 800 cal deficit.

Fitbit reports you burned 2400 in the day, or say 1200 for noon.
MFP takes the Fitbit burn to that point, and estimates the day out, so 2400.
Fitbit 2400 - 2000 MFP estimated = 400 calorie positive adjustment
400 + 1200 eating goal = 1600 eating goal now to burning 2400, still 800 cal deficit.

That 400 could have been exercise, increased daily activity, or perhaps big intense exercise and lazy daily activity, or combo.

Now you log in MFP that you burned 600 in Zumba at this time for this duration, it replaces Fitbit's estimate, which say was 300.
2400 - 300 + 600 = 2700 daily burn.

MFP gets that stat back now and does the same math.
Fitbit 2700 - 2000 MFP estimated - 600 MFP knows about = 100 cal positive adjustment.
100 + 600 + 1200 eating goal = 1900 eating goal now to burning 2700, still 800 cal deficit.


As to why you got negative adjustment after logging Zumba on MFP - you may have logged less calories than Fitbit saw, and the total daily burn by Fitbit was less than what MFP thought you'd burn.
Fitbit original 2400 - 600 Fitbit saw + 300 you logged = 2100 Fitbit adjusted.
MFP does:
2100 - 2000 MFP estimated - 300 MFP knows about = -200
-200 + 300 + 1200 = 1300 eating goal now.

Along those lines with whatever your exact numbers are.


And no - you should not be logging Zumba manually, that is exactly the kind of step based activity it'll get a better estimate of (still estimate), and walking for sure, unless steep incline or carrying weight or pushing weight (it doesn't know about that).

And more accurate calorie burn is going to be on step-based exercise only.
Swimming should be obvious as wrong, but also bike, rowing, lifting, elliptical, ect, all non-step based exercise.