Is my fitbit adjustment (mostly) accurate?

ryanidk

Hey guys, I just recently got my Charge 2, I've read the FAQ a bunch and have tried to get everything as accurate and set as possible. I understand there's some variance with these devices, but I want to know if I maybe have something set wrong.

Some numbers:
I'm 254lbs, 6'0", 24 years old.
Went for a 30min bike ride today(which fitbit estimated about 400 cal burn), went to the gym (left the fitbit on, I understand this can cause some inflation with lifting. I logged the weights on MFP but don't see any adjustment from that), then went to work.

I work in a restaurant where I'm on my feet for about 7 hours straight, walking around. I logged about 20k steps. I set my stride length to 30.4/walk and 43.9/run as per the method for calculating found in the FAQ

Fitbit is giving me an adjustment of 2400 extra calories, for a total of nearly 4400 calories. And that's set for losing 2lbs a week.

I'm a big dude with an active job but I'm possibly worried I might have something set wrong to get THAT large of an adjustment. I don't think I could even eat 4400 calories in a single day.
.

carolemack

What is your Activity Level set at? If you have it set at 'sedentary' it could cause this large a discrepancy when you are as active as you are.

ryanidk

It's set to "Lightly Active" which is probably one tier under what I should set it as, but that's not really the issue here. Even if I had it set higher, it'd still be telling me I could eat 4400 calories today and still be on track for losing 2lbs a week.

heybales

BTW - you didn't get a total of nearly 4400 calories ... because you are set for 2 lbs weekly.

You got the 4400 calories because MFP added 2400 to 2000 to end up at 4400
MFP should be estimating you'd be at 3052 daily burn. BMR 2180 x 1.4 Lightly Active = 3052
Daily burn 3052 - 1000 for 2 lbs weekly = 2052 eating goal.

If you got 2400 adjustment, then Fitbit should have been saying you burned 5450. Less 1000 = 4450.

So the math is correct. The figures they are based on may not be though.

The 4400 has nothing to do with activity level settings on MFP or Fitbit, weight loss settings, ect.

BMR (gender, age, weight, height), and stride length setting. That's what calculated your daily burn on Fitbit.

You sure you have an over 2.5 ft stride length?

When you did a set distance walk to calculate stride length - did you make it your avg daily pace - probably 2 mph or tad less?
That will seem very slow, but with daily job much slower and so many steps, you want that stride length for pace right in the middle so Fitbit can adjust both up and down for actual stride length as needed.

And with that many steps - accuracy of daily activity step distance is more important.

And your MFP setting for activity level has no bearing on your Fitbit daily calorie burn as you point out.
Only the size of the adjustment - end of the day MFP is going to correct itself to whatever Fitbit was at for the day.

One other thing for that many steps, would be a decent number of false steps.
Now, they should still be minimal distance/calorie steps if really from say arm movements - but enough even of small steps can add up to decent inaccuracy.

I'm sure it wouldn't be easy - but perhaps a way to count actual steps after looking at watch, get to say 50 right foot steps, then look. If after normal work actions it's much higher than 100 more total steps - may have an issue with false steps.
Device on body may be better option to leave arm movement out of picture when at work.

A 400 cal burn at 30 min bike ride would also have to be pretty intense.
So it may be since it's going on HR-based calculations - it's still trying to figure out a good burn rate for you - can take 2 weeks.

Also - if the Lifting doesn't show up with a calorie burn in the Exercise Diary - you didn't log it as a workout, and Fitbit kept it's inflated estimated in the daily calorie burn.
I'd use Fitbit database anyway - better accuracy potential, though that is small enough it really doesn't matter.

ryanidk

Thanks for all the info, it could be that my stride length is set too high. I calc'd it at a little above 2mph, which was the inbetween the guide said to find, but I didn't really consider how much slower/smaller my steps could be at work. I'll work on adjusting that tonight.

As an aside, should I leave the "automatically adjust stride length" turned on? Or turn it off?

heybales

I'd leave off.
I believe it's looking for a good valid GPS track distance, taking the steps, and setting it based on that whenever it can.

Problem is, that could have been far removed from average daily pace, in locations GPS and known distance are unavailable.

And even GPS tracks are only potentially accurate to 10 ft, add corners and not best signal and it can be much worse than that.