Higher calories with Fitbit. Evidence it may be inaccurate

thielke2015
thielke2015 Posts: 212 Member
edited November 2024 in Health and Weight Loss
Now, the new thing which I am noticing over the course of 5 days I have been using it. I think it is estimating too higher calorie burn.
Bear with and I will explain. I think I also have evidence to prove this.

I did MFP for 1 year. My weight stagnated about 3 months ago when I decided to give my body a rest from reduced calorie intake. So I lost 35 pounds from november 2016 to August 2017.
I worked out my TDEE online and it averaged between 2,100 - 2,200 this seemed to be in keeping with MFP projection of a daily calorie intake of 1,450 for a 1.5lb weight loss per week 2,200 - 750 = 1,450. It averaged out at 1.1lbs weight loss a week ( which I was happy with). So this has led me to believe my TDEE was somewhere between 1,950 - 2,050.

So, I have been eating for the last 3 months around 1,700 - 1,900 per day.... so more of a maintaining state really and I have maintained. Not lost and not gained.

So, i have had a Fitbit and been wearing it for 5 days now. I am generally burning TDEE between 2,650-2,850 calories per day! I know all about BMR and the calories I will burn for just going about my daily business.
My question is...... going by the evidence I have laid out above this seems incorrect. Because
1.) if my TDEE was this high then I would still have been losing weight the last 3 months because 2,650-2,850 - 750 would have worked out between 1,900 - 2,100 and I have been eating just under this.
2.) if my TDEE really is 2,650-2,850 then I am in a deficit of 1,250 as a minimum! 2.5lb weight loss a week! I don’t think so. This is impossible.

So, it my Fitbit Alta HR giving me inaccurate calorie burns.

Thank you for reading. Looking forward to some opinions

Replies

  • katnadreau
    katnadreau Posts: 149 Member
    I've heard it takes about 4 weeks for your Fitbit to adjust to your personal burns. Im currently in the middle of a 4 week experiment to test the accuracy of my Fitbit Alta HR. I got mine mid September and have worn it non stop aside from showers and charging. I have a spread sheet and everything. Based off the first week my Fitbit calculations are pretty spot on, but I won't come to any serious conclusions until after I complete a least four weeks, possibly six since I am female and have pretty crazy fluctuations ☺
  • maybe1pe
    maybe1pe Posts: 529 Member
    I think it does take some time for your Fitbit to get to you know and have enough data to be accurate. That being said I know for some it is accurate, like me. And for others it is over or under estimating calories depending. The only real way to figure it out is to give it time to get to know you and then test it.
  • thielke2015
    thielke2015 Posts: 212 Member
    Thanks guys. I’ll have to be a bit more patient
  • ladyhusker39
    ladyhusker39 Posts: 1,406 Member
    I noticed a jump in my calories burned when I switched from a Charge HR to the Alta HR. It's been about a month now and it seems to be more in line with the old one.
  • robwilkens42
    robwilkens42 Posts: 8 Member
    I stopped using fitbit a year or two ago because it was just giving me way too many calories to eat every day, and i tried a variety of their products over the years. I mean even factoring in my BMR, on a day where i did nothing but sit on the recliner, i think the fitbit might give me the equivalent of 500-1000 extra exercise calories (beyond the base burn). By that i mean it might say i burned 2500-3000 calories where at the time my bmr would've had me closer to 2000 calories or less per day. Basically, using the fitbit numbers i was unable to lose weight. I think it's because it was using heart rate and my heart rate is elevated often due to anxiety issues (or who knows what else) and it's taking that as 'exercise' meanwhile it -- wasn't.
  • Maxxitt
    Maxxitt Posts: 1,281 Member
    Your anecdote is why data collection over several months is golden :)
  • thielke2015
    thielke2015 Posts: 212 Member
    robwilkens42 wrote: »
    I stopped using fitbit a year or two ago because it was just giving me way too many calories to eat every day, and i tried a variety of their products over the years. I mean even factoring in my BMR, on a day where i did nothing but sit on the recliner, i think the fitbit might give me the equivalent of 500-1000 extra exercise calories (beyond the base burn). By that i mean it might say i burned 2500-3000 calories where at the time my bmr would've had me closer to 2000 calories or less per day. Basically, using the fitbit numbers i was unable to lose weight. I think it's because it was using heart rate and my heart rate is elevated often due to anxiety issues (or who knows what else) and it's taking that as 'exercise' meanwhile it -- wasn't.

    I had read about this. Although it does seem to be tracking my heart rate ok. Eg, when I am exercising..... mainly walking my heart rate is getting to 112 and my restin* heart rate is 73 when asleep. When I’m just doing normal stuff like sitting or cooking etc it is around 79-83. So I thin’ this is an accurate picture of my heart rate. But I did try turning the heart rate monitor off for 24 hours. It didn’t really make a difference on calories burned.
  • robwilkens42
    robwilkens42 Posts: 8 Member
    thielke2015 wrote: »
    I had read about this. Although it does seem to be tracking my heart rate ok. Eg, when I am exercising..... mainly walking my heart rate is getting to 112 and my restin* heart rate is 73 when asleep. When I’m just doing normal stuff like sitting or cooking etc it is around 79-83. So I thin’ this is an accurate picture of my heart rate. But I did try turning the heart rate monitor off for 24 hours. It didn’t really make a difference on calories burned.

    I gather my 'resting' heart rate is closer to '90-95' typically. I've recently learned through a blood test i have a bit of inflammation which i'm trying to address now (may involve long term prednisone/steroid), and suspect that may have been affecting the resting heart rate (the body acts like it's fighting a disease all the time, some kind of -- i'm told - auto-immune issue possibly). It's possible if i get that fixed, something like an all day heart rate monitor may be more accurate, i'm only guessing though.
  • toxikon
    toxikon Posts: 2,383 Member
    There's a few articles floating around saying that fitbits can be up to 27% inaccurate with calorie burns, I believe.
  • SezxyStef
    SezxyStef Posts: 15,267 Member
    there is no tracker or machine out there that can accurately track our calorie burns (outside a lab)

    I find most people have to give their tracker some time to adjust.

    For example I am active....I do 2x 20min walk through the day, I take stairs and move a lot at the office. I then come home and do a weight training session, clean/tidy the house and get dinner ready and then I do a 3 mile run or walk.

    I average an extra 700 calories a day for those activities...

    is it over...possibly but i am not gaining weight and I am losing (slowly) the last couple vanity pounds and I am leaning out.

    I am pretty confident that the burns are pretty close.
  • thielke2015
    thielke2015 Posts: 212 Member
    I am wondering whether to have my previous app ‘walkmeter app’ to sync my calories from walking over to my fit bit as well as my food.
    Disable the exercise thing on the Fitbit. Then see what I burn in a day on Fitbit without any exercise added.
  • SezxyStef
    SezxyStef Posts: 15,267 Member
    thielke2015 wrote: »
    I am wondering whether to have my previous app ‘walkmeter app’ to sync my calories from walking over to my fit bit as well as my food.
    Disable the exercise thing on the Fitbit. Then see what I burn in a day on Fitbit without any exercise added.

    then there is no point to the fitbit.

    Give it some time...
  • NorthCascades
    NorthCascades Posts: 10,968 Member
    SezxyStef wrote: »
    there is no tracker or machine out there that can accurately track our calorie burns (outside a lab)

    A power meter will never be wrong by more than 5%.
  • SezxyStef
    SezxyStef Posts: 15,267 Member
    NorthCascades wrote: »
    SezxyStef wrote: »
    there is no tracker or machine out there that can accurately track our calorie burns (outside a lab)

    A power meter will never be wrong by more than 5%.

    http://www.cyclingweekly.com/news/latest-news/huge-scientific-study-shows-inaccuracies-popular-power-meters-330322

    sure...
  • NorthCascades
    NorthCascades Posts: 10,968 Member
    If that was true, nobody would be able to train with power. You just found the equivalent to starvation mode.
  • SezxyStef
    SezxyStef Posts: 15,267 Member
    NorthCascades wrote: »
    If that was true, nobody would be able to train with power. You just found the equivalent to starvation mode.

    sure.

    https://www.ncbi.nlm.nih.gov/pubmed/28482367
    https://www.welovecycling.com/wide/2017/06/02/accuracy-leading-power-meters-questioned-swiss-laboratory-study
  • rheddmobile
    rheddmobile Posts: 6,840 Member
    Studies have found that people with trackers lose less weight than those without, and this is one reason why. It's kind of fascinating to me that fitbits are now seen as an essential weight loss tool when all research has found the opposite.
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