Are fitbit calories accurate?

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hesn92
hesn92 Posts: 5,967 Member
in Health and Weight Loss
I set my goal to lose 1 lb a week and my activity to "not active" and then as the day goes on, mfp adds calories onto my goal depending on how many steps I take. Is this accurate? Can I just trust it and eat whatever it tells me I can eat? Like yesterday it gave me an extra 450 calories and I didn't work out or anything. I took my dog for a walk, took a total of 8000 steps. That doesn't seem right?

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  • Seffell
    Seffell Posts: 2,222 Member
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    Mine oversetimates by about 300 cal per day only from walking.
  • laurenebargar
    laurenebargar Posts: 3,081 Member
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    Most people eat about half of the calories that get added in from excerise. If your not comfortable eating them and your not hungry you can try not eating them for a few weeks and see how you feel. Or try eating 50% back and see how your weight loss goes.
  • yondaime8
    yondaime8 Posts: 103 Member
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    Experimenting is the only way to know for sure.
  • inertiastrength
    inertiastrength Posts: 2,343 Member
    edited May 2017
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    Mine is pretty accurate too... like a previous poster mentioned, only way to tell is experimenting with your rate of loss and data.

    ETA I have the Alta (not the HR version)
  • tinkerbellang83
    tinkerbellang83 Posts: 9,136 Member
    edited May 2017
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    Accuracy changes from person-to-person and model-to-model. I used a spreadsheet that another user created and my tracker is actually underestimating my calorie burns by 2%.

    The 50% option is a good place to start if you want to avoid gaining weight as a result of eating back over-estimates. If you stick to your calorie goal and the percentage you should be able to review in a few weeks time whether the rate of loss matches your MFP settings.

    That said - yesterday I didn't "work out" just walked to/from work (about 3km each way), I'm set to Lightly Active and my calorie adjustment for the day was over 550 (11,229 steps), so depending on your stats 450 might not be too far off wrong for walking 8000 steps.

  • xXGearheadXx
    xXGearheadXx Posts: 56 Member
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    My gains and losses on the scale follow pretty closely LONG TERM to MFP with a fitbit adjustment.
  • fitmom4lifemfp
    fitmom4lifemfp Posts: 1,575 Member
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    hesn92 wrote: »
    I set my goal to lose 1 lb a week and my activity to "not active" and then as the day goes on, mfp adds calories onto my goal depending on how many steps I take. Is this accurate? Can I just trust it and eat whatever it tells me I can eat? Like yesterday it gave me an extra 450 calories and I didn't work out or anything. I took my dog for a walk, took a total of 8000 steps. That doesn't seem right?

    They are not accurate for me. That's all I can tell ya.
  • SusanMFindlay
    SusanMFindlay Posts: 1,804 Member
    edited May 2017
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    laurenebargar wrote: »
    Most people eat about half of the calories that get added in from excerise. If your not comfortable eating them and your not hungry you can try not eating them for a few weeks and see how you feel. Or try eating 50% back and see how your weight loss goes.

    That's using the MFP database numbers, though. FitBit is more accurate than that for most people (though there will, of course, be outliers who fall at the bottom end of the metabolic bell curve like fitmom4lifemfp).

    The OP set herself to "sedentary" on MFP. Sedentary on MFP is really really really sedentary. Like "sit on your butt all day" sedentary. 2,000-3,000 steps, max. If she's regularly getting 8,000 steps/day, she's actually on the upper end of "lightly active" (or lower end of "active" if there were a decent number of hills/stairs/etc.). Depending on her height and weight, that could easily be a difference of 450 calories. For me, the calorie increase from activity level to activity level is about 300, so 450 calories would be one and a half activity levels above sedentary. Sounds pretty reasonable to me.

    Now, all of this assumes that her food is being logged accurately and that she has a relatively average metabolic rate. If not, she could decide that she wants to leave 100-200 calories for wiggle room. But it's worth noting that she could just as easily have a slightly fast metabolism as a slightly slow one. So, the amount of wiggle room chosen should depend on the target deficit. For a conservative deficit (e.g. 0.5 pounds/week), leaving a little wiggle room ought to be very safe. For an aggressive deficit (anything over 1 pound/week), eat back all the FitBit calories for now.

    After a month or two of using the FitBit and accurately logging food, you know whether it reads high, low or perfectly for you and can adjust accordingly. FWIW, mine gauges my activity level and calories burned almost perfectly - which is a darn good thing because MFP doesn't have an appropriate activity level option for me and neither do TDEE calculators.
  • hesn92
    hesn92 Posts: 5,967 Member
    edited May 2017
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    Thank you, that was helpful.

    I just noticed that The calories burned per mfp does not jive with my fitbit app. Mfp told me yesterday to eat 2000 calories (including exercise) so that would tell me mfp thinks I'm burning 2500. But fitbit told me I burned 2300 calories. So that's only a 300 calorie deficit.

    These darn things.
  • not_a_runner
    not_a_runner Posts: 1,343 Member
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    Mine seems to regularly clock in about 500 calories above my TDEE.
    So no, for me I am definitely not going to eat what my FitBit suggests!
  • TeaBea
    TeaBea Posts: 14,517 Member
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    yondaime8 wrote: »
    Experimenting is the only way to know for sure.

    This^

    It's going to depend upon your FitBit model, your activity type, the accuracy of your food logging. TDEE is always an estimate there are a number of factors FitBit can't know about you. FitBits are pedometers; they aren't equally accurate for all types of activity. Everyone thinks they log food correctly.....food scale vs. measuring cups vs. eye-balling.

    A random poll won't help here.
  • TeaBea
    TeaBea Posts: 14,517 Member
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    hesn92 wrote: »
    Thank you, that was helpful.

    I just noticed that The calories burned per mfp does not jive with my fitbit app. Mfp told me yesterday to eat 2000 calories (including exercise) so that would tell me mfp thinks I'm burning 2500. But fitbit told me I burned 2300 calories. So that's only a 300 calorie deficit.

    These darn things.

    A FitBit should "sync" to MFP (there are issues from time to time) ..... it brings in FitBit calories.....and gives you a deficit based on "I want to lose xx pounds per week."

    Also look into negative calorie adjustments........

    Here's a link to FitBit FAQ's
    http://community.myfitnesspal.com/en/discussion/10098937/faq-syncing-logging-food-exercise-calorie-adjustments-activity-levels-accuracy/p1
  • StaciMarie1974
    StaciMarie1974 Posts: 4,138 Member
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    First, if you walk 8000 steps in a day you are more active than sedentary which is the lowest setting on MFP.

    For me, Fitbit is accurate. I believe this to be true because if on average I eat under what Fitbit says I burned, I lose weight.

    Until you have some data to judge from, there is nothing wrong with assuming that Fitbit is not accurate for you, because you don't know that it is. So assume its 90% accurate. If Fitbit says you burned 2500 in a day, assume 250 (10%) to be potential error. Leave those calories 'on the table'. Then in 4, 8, 12 weeks assess your progress. IF you are losing faster than expected, eat back more of the excess calories.
  • kshama2001
    kshama2001 Posts: 27,898 Member
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    hesn92 wrote: »
    Thank you, that was helpful.

    I just noticed that The calories burned per mfp does not jive with my fitbit app. Mfp told me yesterday to eat 2000 calories (including exercise) so that would tell me mfp thinks I'm burning 2500. But fitbit told me I burned 2300 calories. So that's only a 300 calorie deficit.

    These darn things.

    Did you get your FB number at the end of the day? MFP acts under the assumption that you will live to midnight, but FB doesn't want to go out on a limb like that.

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