My Fitbit total calories for the day are HUNDREDS below my BMR

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Replies

  • heybales
    heybales Posts: 18,842 Member
    Just to confirm - no exercise logging on MFP of say 1 calorie, or grossly underestimated burn?

    Have you looked at the Fitbit 24 hr graph of steps and confirmed it's seeing when you are actually moving?
    If you see flat line when you know you were walking - that's a problem.

    Then again, daily burn shouldn't be under BMR.
    So while there looking at graph of steps - go over to calorie burn - highlight an hour of sleeping with no steps to see total burn x 24 to see what they are using for BMR.

    If well below your BMR - stats on device got off somehow?
    Update body stats lately?
  • PAV8888
    PAV8888 Posts: 13,393 Member
    Guys idk what to do I’m about to smash this thing. Now it’s broken again... it’s saying 1200 calorie burn TOTAL including exercise and BMR (my bmr is minimum 1600) for the whole day... it’s wildly inaccurate. I’m going to be returning it :(

    by definition fitbit cannot be giving you a TDEE reading below your BMR, unless there is an egregious technical issue with your account.

    Even if it detects NOTHING it should be giving you a reading equal to BMR. If support cannot intervene to resolve, then yes, I would return and delete the account.

    Alternatively I would consider creating a new fitbit account and asking them to transfer the fitbit to the "new owner".
  • deannalfisher
    deannalfisher Posts: 5,600 Member
    Honestly ignore your Fitbit if it’s wrong - mine consistently tells me I only burn 1500 cal a day yet I maintain on 2700
  • PAV8888
    PAV8888 Posts: 13,393 Member
    edited March 2020
    Honestly ignore your Fitbit if it’s wrong - mine consistently tells me I only burn 1500 cal a day yet I maintain on 2700

    Wow! Second report of Fitbit giving back BMR or near BMR numbers, right? 1500 day in total is basically BMR or near BMR with almost no activity detected. Is it just not detecting your steps and activity @deannalfisher ? Or is it detecting them but not giving you calories for them? Have you asked support?
  • deannalfisher
    deannalfisher Posts: 5,600 Member
    PAV8888 wrote: »
    Honestly ignore your Fitbit if it’s wrong - mine consistently tells me I only burn 1500 cal a day yet I maintain on 2700

    Wow! Second report of Fitbit giving back BMR or near BMR numbers, right? 1500 day in total is basically BMR or near BMR with almost no activity detected. Is it just not detecting your steps and activity @deannalfisher ? Or is it detecting them but not giving you calories for them? Have you asked support?

    Admittedly covid19 has me much less activity than normal but fitbit istelling me with 4000 steps; 5’3” and 165lbs tgat I only burned 1350 cal today...
  • PAV8888
    PAV8888 Posts: 13,393 Member
    edited March 2020
    Admittedly covid19 has me much less activity than normal but fitbit istelling me with 4000 steps; 5’3” and 165lbs tgat I only burned 1350 cal today...

    Is the 1350 by midnight or to this point of the day? How many hours left?

    4000 is just about at the top end of sedentary, i.e. about an activity factor of 1.2 to 1.25 for the day.

    BMR of about 1338 (random age used). Means "expected" calories if all day ends at 4K steps would be 1675ish

    Based on your 2700 maintenance... you would be looking at an activity factor of about 2x BMR... which would be very very active... or you being an outlier :smile:

    Based on what I remember you posting, I believe you're a higher burning outlier (like Anne) with either Fitbit not detecting all your movement, or you registering as high "active" or low "very active" in terms of activity in the 12K step range (so BMR x 1.7 approximately), but burning at BMR x 2.

    Which means that you would be looking at an approximately 18% correction of what your fitbit gives you as your calories and could adjust based on that if you felt like it.
  • yirara
    yirara Posts: 9,329 Member
    Another funny number: roughly 19km walk through forests, flat landscape, Fitbit gave me a whopping 1560kcal for that! I think these are gross calories, thus lets take the bmi off. https://scoobysworkshop.com/calorie-calculator/ gives me a bmi of roughly 1400 (small, not heavy, old-ish). Thus for this 4.5h trip it would 262, thus 1300 net calories for this walk. Nope.
  • heybales
    heybales Posts: 18,842 Member
    yirara wrote: »
    Another funny number: roughly 19km walk through forests, flat landscape, Fitbit gave me a whopping 1560kcal for that! I think these are gross calories, thus lets take the bmi off. https://scoobysworkshop.com/calorie-calculator/ gives me a bmi of roughly 1400 (small, not heavy, old-ish). Thus for this 4.5h trip it would 262, thus 1300 net calories for this walk. Nope.

    How far off using a gross calculator since Fitbit is correctly telling you how much you burned doing whatever you did during that chunk of time?
    Usually it's walking/running calculations are right on if it got the distance correct.
    The problem is when it slips into HR-based calculations and you were barely into decent range for that estimate.

    https://exrx.net/Calculators/WalkRunMETs

    Because 288 cal an hr does seem low for walking.

  • yirara
    yirara Posts: 9,329 Member
    heybales wrote: »
    yirara wrote: »
    Another funny number: roughly 19km walk through forests, flat landscape, Fitbit gave me a whopping 1560kcal for that! I think these are gross calories, thus lets take the bmi off. https://scoobysworkshop.com/calorie-calculator/ gives me a bmi of roughly 1400 (small, not heavy, old-ish). Thus for this 4.5h trip it would 262, thus 1300 net calories for this walk. Nope.

    How far off using a gross calculator since Fitbit is correctly telling you how much you burned doing whatever you did during that chunk of time?
    Usually it's walking/running calculations are right on if it got the distance correct.
    The problem is when it slips into HR-based calculations and you were barely into decent range for that estimate.

    https://exrx.net/Calculators/WalkRunMETs

    Because 288 cal an hr does seem low for walking.

    Ehm.. no. Assuming Fitbit displays gross calories in the exercise overview, that's 1560 calories.
    BMI over 4.5 hours = 262.
    Net calories for the walk = 1560-262 = 1400-ish. Mind you, I did not walk the whole time as I was also playing a location-based game.
    1400 net calories for a 20km walk in flat terrain is total and utter tosh. I'd not burn that much if I was running this distance.