Are FitBit and MyFitnessPal double-counting runs?

[RocksSoxBills14]

Hi all,

I tried searching the community for this first, and I couldn't find anything myself, so my apologies if this has been asked and answered.

I have a FitBit Charge 3 that I use for... well, all the stuff a FitBit is used for, including specifically tracking runs and workouts. I also use MapMyFitness when I run, and they both tie into MyFitnessPal for calorie tracking. 

MapMyFitness writes to FitBit, so that when I go into Exercises in the FitBit app, it shows any workouts (usually runs) tracked with MapMyFitness alongside of those tracked with FitBit. Both of these apps also write to MyFitnessPal for calorie tracking.

My question is if FitBit and MyFitnessPal are double counting these exercises and severely overestimating how many calories I've burned in a day? In glancing at it, it always seemed as if at least MFP was only counting steps from FitBit, and counting the runs from MapMyFitness, but now I wonder if the FitBit-tracked runs are calculated into the calories burned from steps? For example, today I ran a mile at about a 7:30 pace, and as of this writing I have 9,094 steps; in my MFP Diary, it shows "FitBit Tracker calorie adjustment -791; Running (8 minutes) -141." Is that 791 FitBit calorie number including the FitBit-tracked run, or did MFP delete those calories out because it sees the run from its partner app?

Thanks everyone for your help with this! I'm trying to lose ~20 last stubborn pounds (down ~30 from where I started), and I want to be as accurate as possible!

[RocksSoxBills14 · Accepted solution]

UPDATE: So I did some more googling last night, and found that it shouldn't be double counting runs, but a good way to check is to go for a run normally (tracking with both FitBit and MMF), and at the end, "Finish" the workout on Fitbit, but only pause it on MMF. Then, sync FitBit and MFP to see the calorie adjustment there, then Finish and Save the MMF run to sync that in... if the FitBit calories adjust down, then it isn't double counting and if they don't, it is being double counted.
I did all of this today, and after all of the syncing, I found that tracking with both does not double count runs. When I synced in the run from MMF, MFP took that ~500 calories from the FitBit line and put it onto the MMF Run line.
So, there we go. Thanks for reading all of this, and I hope that this maybe helps someone else down the line?