Fitbit calorie estimation

ForecasterJason
ForecasterJason Posts: 2,577 Member
edited November 2024 in Fitness and Exercise
I have the Fitbit One, and while I do like it, one thing I am concerned about is whether it could be significantly over-estimating how many calories I'm burning. My suspicion is mostly centered on intentional exercise, although I'm also questioning whether it may be over-estimating normal daily activity. For instance, I played basketball for 30 minutes today. In roughly the same time period that I played, it showed nearly 250 calories burned. I'm only 5'8" 124 lbs, so I thought this seemed like it may be excessive. There are other days that I've played basketball and had it show a similar calorie burn, so this wasn't just an unusual occurrence.

Thoughts?

Replies

  • Christine_72
    Christine_72 Posts: 16,049 Member
    Sorry, I can't get past 124lbs at 5"8...

    As for your calorie burn it sounds plausible.
  • editorgrrl
    editorgrrl Posts: 7,060 Member
    The only way to gauge the accuracy of your Fitbit is to trust it for several weeks, then reevaluate your progress.

    Connect your accounts at http://www.myfitnesspal.com/fitbit

    Set your goal to .5 lb. for every 25 lbs. you're overweight: http://www.myfitnesspal.com/account/change_goals_guided

    Enable negative calorie adjustments: http://www.myfitnesspal.com/account/diary_settings

    Ignore your Fitbit calorie goal and follow MFP's, eating back your adjustments. No need to log any step-based activity—your Fitbit is tracking it for you. Log non-step exercise (like swimming or biking) either in Fitbit or in MFP—never both. Exercise logged in MFP overwrites your Fitbit burn during that time.

    You can learn more in the Fitbit Users group: http://community.myfitnesspal.com/en/group/1290-fitbit-users
  • ForecasterJason
    ForecasterJason Posts: 2,577 Member
    edited September 2015
    I wanted to update this thread since I got on the treadmill today while wearing my Fitbit. I had the treadmill adjusted for my weight. It showed my calorie burn at just under 150 for 40 minutes of walking at an average of 3.3 mph with a slight incline. In that same time period, my Fitbit showed about 275 calories burned. I think this figure is suspect, considering that my exercise intensity was moderate but not that vigorous.

    I like using my Fitbit to track my daily calorie burn, but again I'm wondering if it's overshooting my calorie burn estimate by a good bit. I think it's worth noting that since I started this thread, it has been consistent in showing roughly the same number of calories burned when I play basketball as what I stated months ago.
  • shadow2soul
    shadow2soul Posts: 7,692 Member
    Keep in mind your Fitbit calorie burn includes your BMR.
    I found the models without HR underestimated my total daily calorie burn by 200 calories per day on average.
    On your Fitbit profile page (website not app) you should see a 30 day average burn and a 30 day average intake.
    30 day average burn - 30 day average intake = 30 day average deficit or surplus
    (30 day average deficit or surplus * 30)/3500 = expected loss or gain
    Compare that to what your weight did and you will have your answer.
  • ForecasterJason
    ForecasterJason Posts: 2,577 Member
    edited January 2016
    Ok, so I know Fitbit includes BMR when exercising, but still I have to question the accuracy of this. Supposedly, a couple days ago I burned 10-11 calories in one minute by jogging backwards at an average speed of 5.2 mph (it showed 50-55 calories for a 5 minute time period). I could see if I was 200 lbs, but at 124 lbs I fail to see how that can be true.
  • rileysowner
    rileysowner Posts: 8,345 Member
    ForecasterJason wrote: »
    I have the Fitbit One, and while I do like it, one thing I am concerned about is whether it could be significantly over-estimating how many calories I'm burning. My suspicion is mostly centered on intentional exercise, although I'm also questioning whether it may be over-estimating normal daily activity. For instance, I played basketball for 30 minutes today. In roughly the same time period that I played, it showed nearly 250 calories burned. I'm only 5'8" 124 lbs, so I thought this seemed like it may be excessive. There are other days that I've played basketball and had it show a similar calorie burn, so this wasn't just an unusual occurrence.

    Thoughts?

    For height, sex, weight, and age your would likely burn 230 half-court to about 310 full-court for 30 minutes of playing basketball unless you are just standing around.

    All the reading I have done tends to make me think that fitbits are fairly accurate in their estimation. They are meant not so much for a specific exercise for a specific period of time, but for total daily calories burned. In other words, stop focusing on the minutia and let it do its job. If you find that the results that come don't match up, then you can start questioning the details.
  • rileysowner
    rileysowner Posts: 8,345 Member
    Just a completely unrelated question, what are your goals? Weight loss, weight gain, maintain, etc?
  • auddii
    auddii Posts: 15,357 Member
    Was it early in the day? Yesterday I went for a walk in the morning and it gave me 750ish calories. I then proceeded to sit on the couch all day and do work. By the end of the day, the adjustment was far lower because I did not walk as much as it expected.
  • ForecasterJason
    ForecasterJason Posts: 2,577 Member
    rileysowner wrote: »
    ForecasterJason wrote: »
    I have the Fitbit One, and while I do like it, one thing I am concerned about is whether it could be significantly over-estimating how many calories I'm burning. My suspicion is mostly centered on intentional exercise, although I'm also questioning whether it may be over-estimating normal daily activity. For instance, I played basketball for 30 minutes today. In roughly the same time period that I played, it showed nearly 250 calories burned. I'm only 5'8" 124 lbs, so I thought this seemed like it may be excessive. There are other days that I've played basketball and had it show a similar calorie burn, so this wasn't just an unusual occurrence.

    Thoughts?
    In other words, stop focusing on the minutia and let it do its job. If you find that the results that come don't match up, then you can start questioning the details.
    Yeah, I guess this is probably what I should be doing. It seems to have my TDEE about right (I think it does overestimate by 50-100 calories). That being said, when I'm playing basketball I'm doing it alone and on my driveway. So it may be that it overestimates calories burned while I'm moving, but it evens out since it doesn't track upper body movements (and I can't use it in the shower).

    I did my jogging on Saturday around noon. I have to admit, I do think the total calories it had for that day was about right, but I just have a hard time believing the calories burned while exercising.

    I'm basically trying to maintain my weight at the high end of my maintenance range, or just barely get into a calorie surplus. So given my estimation of it being off by up to 100 calories, I'm trying to shoot for the TDEE it gives.

  • Christine_72
    Christine_72 Posts: 16,049 Member
    ForecasterJason wrote: »
    Ok, so I know Fitbit includes BMR when exercising, but still I have to question the accuracy of this. Supposedly, a couple days ago I burned 10-11 calories in one minute by jogging backwards at an average speed of 5.2 mph (it showed 50-55 calories for a 5 minute time period). I could see if I was 200 lbs, but at 124 lbs I fail to see how that can be true.

    124lbs, is that a typo?
  • ForecasterJason
    ForecasterJason Posts: 2,577 Member
    Christine_72 wrote: »
    ForecasterJason wrote: »
    Ok, so I know Fitbit includes BMR when exercising, but still I have to question the accuracy of this. Supposedly, a couple days ago I burned 10-11 calories in one minute by jogging backwards at an average speed of 5.2 mph (it showed 50-55 calories for a 5 minute time period). I could see if I was 200 lbs, but at 124 lbs I fail to see how that can be true.

    124lbs, is that a typo?
    No. I've always been skinny since my early childhood years.

  • callsitlikeiseeit
    callsitlikeiseeit Posts: 8,626 Member
    ForecasterJason wrote: »
    Christine_72 wrote: »
    ForecasterJason wrote: »
    Ok, so I know Fitbit includes BMR when exercising, but still I have to question the accuracy of this. Supposedly, a couple days ago I burned 10-11 calories in one minute by jogging backwards at an average speed of 5.2 mph (it showed 50-55 calories for a 5 minute time period). I could see if I was 200 lbs, but at 124 lbs I fail to see how that can be true.

    124lbs, is that a typo?
    No. I've always been skinny since my early childhood years.

    please tell me youre not trying to lose weight
  • ForecasterJason
    ForecasterJason Posts: 2,577 Member
    callsitlikeiseeit wrote: »
    ForecasterJason wrote: »
    Christine_72 wrote: »
    ForecasterJason wrote: »
    Ok, so I know Fitbit includes BMR when exercising, but still I have to question the accuracy of this. Supposedly, a couple days ago I burned 10-11 calories in one minute by jogging backwards at an average speed of 5.2 mph (it showed 50-55 calories for a 5 minute time period). I could see if I was 200 lbs, but at 124 lbs I fail to see how that can be true.

    124lbs, is that a typo?
    No. I've always been skinny since my early childhood years.

    please tell me youre not trying to lose weight
    I already posted "I'm basically trying to maintain my weight at the high end of my maintenance range, or just barely get into a calorie surplus."

  • ForecasterJason
    ForecasterJason Posts: 2,577 Member
    I think I figured out what my Fitbit is doing. It turns out that it's overestimating my METs. Today, I walked for about an hour outside, which includes going up and down hills. I covered close to 3 miles, so I was going a little under 3.0 mph. My Fitbit reports that as "Intense" exercise and not "Moderate", which I don't think is correct. I don't think my heart rate was that elevated for what I did to be considered vigorous exercise. And based on a chart I've seen for exercises and METs, it seems like what I did was no more than a 5.5. But based on my BMR and calories burned from that, my Fitibit picked it up as being at least a 7. So, because it overestimates my exercise intensity, my calories burned is inflated.
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