CaloriesCounting and Fitbit

Nysportsred

When people track with their Fitbit how do you figure out/ estimate the calories? I’ve read they are not really accurate and are used more to get a ballpark idea of the number.

It says, for example, I burned 325 calories in 32 minutes of cardio then weights this morning. I put in 200 on MFP but obviously it’s just throwing a number in there.

Interested to see what others do.,

cwolfman13

I get wonky numbers from time to time, but for the most part my FitBit jives pretty close with my own data. You also have to remember that it's not just giving you calories for the exercise, but also the calories you would have otherwise burned sitting on the couch. Also, if you have it synced, you will only get an adjustment on MFP for calories in excess of what is already included in your activity level.

Squish815

I have my Fitbit linked to my MFP account so it updates it for me automatically.

I know that it's not always accurate though so try and only eat back around 75% of the calories it gives me.

kimny72

I have my fitbit Alta (non hrm) sync with mfp and have found the calories pretty accurate

Nysportsred

kimny72 wrote: »

I have my fitbit Alta (non hrm) sync with mfp and have found the calories pretty accurate

Ugh why are mine so off lol. MFP says 230 and Fitbit said 325 on Fitbit. I checked because I thought maybe the weight of my height was different on each when I listed it but it’s the same.

Mines linked but it seems to update on MFP when it feels like it lol. I have to log out of Fitbit 2-3 times for it to actually sync.

The exercise in MFP says 230, Fitbit adjustment says 180, and Fitbit itself says 325.

Apparently I burned 750 by sleeping last night. That sounded odd to me, but I’m new to using the Fitbit regularly.

cmriverside

You're making a few common Fitbit/MFP assumptions that may not be what's actually happening.

Here is the Fitbit group here on this site, lots of info in the FAQs in that group.

RAinWA

I've always logged non-step based exercise in Fitbit and then just let MFP and Fitbit figure it out. I have a Fitbit One (non-HRM) which has been really accurate for me (based on several years worth of data).

Duck_Puddle

Nysportsred wrote: »

kimny72 wrote: »

I have my fitbit Alta (non hrm) sync with mfp and have found the calories pretty accurate

Ugh why are mine so off lol. MFP says 230 and Fitbit said 325 on Fitbit. I checked because I thought maybe the weight of my height was different on each when I listed it but it’s the same.

Mines linked but it seems to update on MFP when it feels like it lol. I have to log out of Fitbit 2-3 times for it to actually sync.

The exercise in MFP says 230, Fitbit adjustment says 180, and Fitbit itself says 325.

Apparently I burned 750 by sleeping last night. That sounded odd to me, but I’m new to using the Fitbit regularly.

Your Fitbit is measuring calories you burn all day long including while sleeping, breathing, being alive, etc. so yes, you probably did burn 750 calories while sleeping (you burn calories all the time as long as you’re alive).

And I think it’s important to understand that your Fitbit calorie adjustment is the difference between what Fitbit things you burned for the entire day (including sleeping, breathing, being alive, all your regular daily activity, exercise, etc) and what mfp thinks you burned for the entire day (which is determined by your height/weight/gender/activity setting on mfp).

So your Fitbit calorie adjustment probably won’t ever exactly match a workout burn (whether the number is from Fitbit or mfp) because that’s not what the adjustment is. The adjustment is the difference in your total calorie burn for the entire day.

During the day, that “total calories burned for the day” number is estimated by Fitbit based on what you’ve done so far, your normal patterns of activity, etc. That number changes throughout the day.

Also-you can sync your Fitbit 7000 times but it generally only transfers over to mfp if you have a new step count. So try just walking around a bit and sucking again. Also-if you’re manually logging exercise (which you likely don’t need to do (unless you have The One model which they don’t sell anymore)), that’s further complicating the syncing (and the calculations).

shadow2soul

Nysportsred wrote: »

kimny72 wrote: »

I have my fitbit Alta (non hrm) sync with mfp and have found the calories pretty accurate

Ugh why are mine so off lol. MFP says 230 and Fitbit said 325 on Fitbit. I checked because I thought maybe the weight of my height was different on each when I listed it but it’s the same.

Mines linked but it seems to update on MFP when it feels like it lol. I have to log out of Fitbit 2-3 times for it to actually sync.

The exercise in MFP says 230, Fitbit adjustment says 180, and Fitbit itself says 325.

Apparently I burned 750 by sleeping last night. That sounded odd to me, but I’m new to using the Fitbit regularly.

Okay so Fitbit gives you a Total Calorie Burn for the day. This includes BMR, daily activity and exercise.

So for example:

I get 14 calories every 15 mins to account for my bodies BMR. This means at 6 am I will see at least a 336 calorie burn to account for the calories my body used to keep me breathing, my heart beating, and so on.
Now my BMR will be less than yours, because I am a 5’4.5” 137lb female. Over the course of the day I will get 1344 calories to account for what my body uses at rest.

Your adjustment on MFP is NOT just exercise. It is a comparison of calories burned in total. The math is:
Fitbit burn - MFP estimate = +/- adjustment

So while you may have burned 325 during the workout, your overall calories burned for the day is only 180 calories higher than what MFP thought you would burn.

A more in depth breakdown:

This is using my information.

MFP Lightly Active = 1894 calories burned

That breaks down to:
78.9 calories per hour
1.3 calories per minute

As of 11:40 am my Fitbit burn is 738 calories. Fitbit sends that number to MFP, but it still leaves 12 hrs 20 mins unaccounted for.
So MFP adds to it based on my Lightly Active setting.

12 x 78.9 = 946.8
20 x 1.3 = 26
972.8 calories based on MFP Lightly Active for the remaining 12 hrs 20 mins in the day. ***This gets adjusted each time Fitbit sends a calorie burn update to MFP***

738 (Fitbit) + 972.8 = 1710

1710 - 1894 = -183

So in my case I am losing calories. MFP won’t take away the full 183, because it would take me below 1200. This however will change as the day goes on. As I become more active I should start to see additional calories.

GottaBurnEmAll

Just to build on what shadow2soul said, since I have my Fitbit set up differently...

I have both Fitbit and MFP set to sedentary. I wake early and go to bed early, so doing my settings this way avoids a large end of day negative adjustment based on an earlier predicted burn due to my high activity level.

Anyway, to my main point... I find my Fitbit to be pretty spot on. In fact, at the end of the day, it gives me less calories (TDEE) than MFP (with the adjustment) does. Not many, just about 90 or so.

So the idea that Fitbits are overly generous always makes me giggle.

Nysportsred

Thanks everyone. I appreciate the input and helping me get it a little more.

Nysportsred

Ok I apologize if this sounds repetitive (community college grad here), but even after reading all the responses again this one doesn’t make sense:

Yesterday I worked out for 63 minutes. Fitbit said 663 calories burned and MFP’s adjustment was 234. I get that. I understand that one from the responses. Today it is just before 10AM my time and the MFP adjustment is 329 yet I really haven’t done anything except get the kids ready for day care, me ready for work, drive to work, walk up the stairs, and sit at my desk.

How come the MFP adjustment is more already today than yesterday despite an intense work out yesterday around 7PM?