Does Fitbit way overestimate calories burned?

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  • editorgrrl
    editorgrrl Posts: 7,060 Member
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    I've got mine set at sedentary too. I've also had it set to lightly active, i can't remember what, if any difference it made.

    If (and only if) you enable negative calorie adjustments in your diary settings, you're still eating the same number of calories—Fitbit burn minus deficit. At lightly active, you'll just start with more calories in the morning and get smaller adjustments.

    Without negative calorie adjustments enabled, you'll never eat at a true deficit on days you burn fewer calories than your activity level.
  • xLoveLikeWinterx
    xLoveLikeWinterx Posts: 408 Member
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    I deliberately set my activity level to sedentary on MFP even though I now usually walk 8 to 10 miles per day.

    I did this because I want my caloric allotment on MFP to give me the base calories I can eat each day without adding in any exercise. I then let my Fitbit calculate my additional calories earned from walking and give me that 'credit' on MFP. I can then easily decide how many calories to eat back in any given day. :)

    I did this for the same reason. I may end up with +400 calories on a day, but that's ok. I wanted my base amount first.
  • RobertWilkens
    RobertWilkens Posts: 77 Member
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    JennyL791 wrote: »
    I just got a Fitbit last week, synced it, and suddenly my "calories burned" tally is so much higher. Even on days where I do no exercise of any kind. I weighed myself this morning, 5 days after I got it, and there has been no change. Should I be ignoring what Fitbit says, either on days when I don't actually exercise, or even on all days? Meaning, should I not be eating those calories back? I'm suddenly reading that this whole "starvation mode" thing is a myth, this is news to me. Some days I can easily have close to 1,000 calories left when I go to bed. Can that be right? Perhaps there's a way to change a setting of some sort somewhere? I'm new to Fitbit and to MyFitness Pal, so please assume no knowledge on my part.

    Thank you!

    When i used FitBit and BodyMediaFit they both give we way too many calories-- eating them 'back' is dangerous. I mean they gave me 1,000 calories exercise credit (BMR around 2,000 + 1,000 = 3,000 calories a day it said i was burning on a slow day).

    I now use a Microsoft Band, and if anything, many days even with 10,000+ steps, it gives me fewer calories than MFP gave me based on my MFP's caclculation of BMR (which you can find on MFP's APP tab) + 510 exercise calories burned/day assumed. I only get credit if i mark exercises as exercises.
  • ScreeField
    ScreeField Posts: 180 Member
    edited June 2015
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    It's 70% for people who are really inactive. I think you're misunderstanding what that means.

    And Fitbit is insanely accurate unless you walk slower than .5 mph if you've got the One, at least.

    Thanks. You're right. My last post wasn't completely clear which caused misinterpretation. I'm under the unfortunate circumstance of typing single-handed and putting fast-moving thoughts on the page with a slow typing speed is difficult.

    Let me clear it up. There's a large margin of error because the first part of the equation is based on a number of factors not captured. The most obvious being body composition, others would be TEF, fluctuations and differences in hormone levels, use of stimulants or depressants, etc. This half of the equation represents 45 to 70 percent of caloric requirements. This percentage is never static.

    The second part of the equation "Activity" has another margin of error. I've researched this for years now comparing competing models and formulas. My current focus is activity trackers (which is why I've tested so many). Interestingly, a popular heart rate monitor company purchases energy expenditure formulas from another company. If you compare their models there is a large variation in output, which is strange since one sold the formulas to the other. And, this is merely the variation between two companies using the same formulas. Although, most of the formulas come from a single body of scientists.

    Here's an example:

    Here's the output for a 1 hour bike ride. Using exactly the same data (data captured from a single HRM unit) and the same base formulas, the two models output the following energy expenditure:

    Model 1: 424 calories
    Model 2: 432 calories

    If I check the same route/time using web-based calculators, the numbers are vastly different.

    Model 3: 232 calories

    So, if we account for even a small margin of error, let's say 5% and apply that to a 2,000 calorie diet. That's + or - 700 calories per week. Fortunately, users of these devices typically have a downward trend of caloric intake and upward trend of activity, which generally makes them "work". But, assuming if it works for one person, it should work the same for everyone is a fallacy.

  • daaaaaanielle
    daaaaaanielle Posts: 114 Member
    edited June 2015
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    earlnabby wrote: »
    I have negative adjustments disabled. I really don't like seeing the red. Same reason I don't pre-log everything I expect to eat until I have enough exercise calories in so I don't go into red. I figure I am following MFP's NEAT numbers and that is my calorie goal without exercise, so I don't need to know anything about calories burned until I get into the plus category.

    I have the negative adjustments disabled too, though for slightly different reasons. I don't like the red at all and I would rather sacrifice a little bit of weight loss for being to eat at a consistent level.

    I pre-log all of my food to fit in with my base calorie goal. When I get positive adjustments, I do one of two things depending on where the adjustment came from. If it's from general walking around, I'll make my dinner a bit bigger, I'll add in ice cream, something like that. If the adjustment came from explicit, deliberate exercise, I'll use the adjustment to have some sort of protein smoothie. If after the smoothie I still have calories left, I play it by ear with whether or not I feel like a bigger dinner. The smoothie does a pretty good job of filling me up though.
  • PeachyCarol
    PeachyCarol Posts: 8,029 Member
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    shell1005 wrote: »
    I still think the idea of "calling other people out on what they exercise" is really just thoughtless and honestly obnoxious.

    We are all in a different journey and to have such an attitude about someone else's workouts is just elitist and judgmental. Someone who took one more step than they took yesterday should be championed and cheered and never looked down upon.

    /end rant

    Cosigned
  • Merkavar
    Merkavar Posts: 3,082 Member
    edited June 2015
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    Orphia wrote: »
    I have to walk around 21,000 steps or over 10 miles to get to that magical 1000 calorie burn. I've been trusting my fitbit, and so far so good.

    10,000 steps with my iPhone 6 Health app gets me a bit less than 2,000 kilojoules.

    Somebody help me with the maths!

    And kudos and amazement @christinev297 for using calories/miles as a fellow Australian. I've barely got the hang of pounds. :)

    I hope I'm not wrong here but 2.2 pound to a kg. 4.18kj to cal and 1.6km to a mile are the conversions I use. Might not be 100% but close enough I think.

    So is calories another one of those measurements that are used by the U.S. and like 3 other countries that are so small you can't even see them on a world map printed on A3 size paper?

    :smiley:
  • Orphia
    Orphia Posts: 7,097 Member
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    Merkavar wrote: »
    Orphia wrote: »
    I have to walk around 21,000 steps or over 10 miles to get to that magical 1000 calorie burn. I've been trusting my fitbit, and so far so good.

    10,000 steps with my iPhone 6 Health app gets me a bit less than 2,000 kilojoules.

    Somebody help me with the maths!

    And kudos and amazement @christinev297 for using calories/miles as a fellow Australian. I've barely got the hang of pounds. :)

    I hope I'm not wrong here but 2.2 pound to a kg. 4.18kj to cal and 1.6km to a mile are the conversions I use. Might not be 100% but close enough I think.

    So is calories another one of those measurements that are used by the U.S. and like 3 other countries that are so small you can't even see them on a world map printed on A3 size paper?

    :smiley:

    Hahahaha, like Fahrenheit and the Imperial system! I'm not sure, but I've found that quite a lot of products only show the kilojoule count here in Australia. I'd like to know if calories are the default in any other countries.
  • Christine_72
    Christine_72 Posts: 16,049 Member
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    Hopefully one day America will catch up to the rest of the world :wink:
  • MamaBirdBoss
    MamaBirdBoss Posts: 1,516 Member
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    Merkavar wrote: »
    Lourdesong wrote: »
    Wait, wait. It just dawned on me. @azulvioleta6 are you talking about 1000 calorie Fitbit Adjustments? (seeing as this is a thread about Fitbit Adjustments)

    If that's the case, ya when I set my profile on MFP to sedentary, I'm almost guaranteed to get a 1000 calorie adjustment from Fitbit. That however isn't just exercise, but includes my daily activity as well. My exercise calorie burns are puny anymore :disappointed: . I'm set to lightly active right now and have a 422 calorie adjustment from Fitbit already.

    Yeah, I think that's what's going on. She has been using "activity" and "exercise" interchangeably.

    However, I have to do something like 30k steps to get anything close to a 1,000 adjustment. I don't have my MFP settings on sedentary, though, I think it's active or lightly active and begin the day with 1463 calories that I set myself with negative adjustment turned off. I weigh 186.

    I'm at 45,600 steps with my short, squatty legs to get 1,000 cal just from activity. lol. And I AM on sedentary!

    That don't make no sense.

    How are you set to sedentary and doing 45k steps and only getting that small of an adjustment. Are you super fit and walking is really easy for you?

    It makes complete sense. I don't weigh that much, and it's walking at a rate I can type and walking around the house, not powerwalking.

    1.) I weigh just over 140lbs.
    2.) MFP/FitBit doesn't give me a positive adjustment until I hit ~3,135 steps per day. (I haven't figure this out quite exactly yet, but it appears to be above 3,000 and below 4,000.)
    3.) FitBit calculates 10,000 strides at 4 miles.
    4.) It takes 17.5 miles (43,750 steps) for a 140lb person to burn 1100 calories.
    5.) After my positive adjustment, that ends up being below 1000 cal.

    This is why I'm looking into a weight vest! Just 40lbs more would burn more than 25% more.
  • MamaBirdBoss
    MamaBirdBoss Posts: 1,516 Member
    edited June 2015
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    earlnabby wrote: »
    I have negative adjustments disabled. I really don't like seeing the red. Same reason I don't pre-log everything I expect to eat until I have enough exercise calories in so I don't go into red. I figure I am following MFP's NEAT numbers and that is my calorie goal without exercise, so I don't need to know anything about calories burned until I get into the plus category.

    I slept most of yesterday, and it MFP refused to adjust all the way down to my "real" burn according to FitBit. But it didn't complain when I closed out my food log with only a bit about 1000 cal, so there's that...lol.

    If I put in a higher activity level and got a huge slash...I think I would just give up in despair. Seriously. I LIKE my sedentary setting, even if I have to deliberately exercise to earn any calories.

    I couldn't deal with the adjustment down while sleeping, either. I mean, WTH, MFP????? Do you expect me to never sleep? Am I supposed to remain "lightly active" while unconscious?

    I don't get that.
  • MamaBirdBoss
    MamaBirdBoss Posts: 1,516 Member
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    editorgrrl wrote: »
    I've got mine set at sedentary too. I've also had it set to lightly active, i can't remember what, if any difference it made.

    If (and only if) you enable negative calorie adjustments in your diary settings, you're still eating the same number of calories—Fitbit burn minus deficit. At lightly active, you'll just start with more calories in the morning and get smaller adjustments.

    Without negative calorie adjustments enabled, you'll never eat at a true deficit on days you burn fewer calories than your activity level.

    It won't adjust your calories all the way down to what FB says, though, if you're fairly light, because it won't go below 1200 cal.

    Me, yesterday. I worked (not on treadmill), cleaned the house, and went to sleep because I was hurting a lot. No deliberate exercise.

    MyFitness Pal Calories Burned 1709

    FitBit Calories burned 1612

    FitBit Calorie Adjustment -20
  • MamaBirdBoss
    MamaBirdBoss Posts: 1,516 Member
    edited June 2015
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    ScreeField wrote: »
    It's 70% for people who are really inactive. I think you're misunderstanding what that means.

    And Fitbit is insanely accurate unless you walk slower than .5 mph if you've got the One, at least.

    Thanks. You're right. My last post wasn't completely clear which caused misinterpretation. I'm under the unfortunate circumstance of typing single-handed and putting fast-moving thoughts on the page with a slow typing speed is difficult.

    Let me clear it up. There's a large margin of error because the first part of the equation is based on a number of factors not captured. The most obvious being body composition, others would be TEF, fluctuations and differences in hormone levels, use of stimulants or depressants, etc. This half of the equation represents 45 to 70 percent of caloric requirements. This percentage is never static.

    The second part of the equation "Activity" has another margin of error. I've researched this for years now comparing competing models and formulas. My current focus is activity trackers (which is why I've tested so many). Interestingly, a popular heart rate monitor company purchases energy expenditure formulas from another company. If you compare their models there is a large variation in output, which is strange since one sold the formulas to the other. And, this is merely the variation between two companies using the same formulas. Although, most of the formulas come from a single body of scientists.

    Here's an example:

    Here's the output for a 1 hour bike ride. Using exactly the same data (data captured from a single HRM unit) and the same base formulas, the two models output the following energy expenditure:

    Model 1: 424 calories
    Model 2: 432 calories

    If I check the same route/time using web-based calculators, the numbers are vastly different.

    Model 3: 232 calories

    So, if we account for even a small margin of error, let's say 5% and apply that to a 2,000 calorie diet. That's + or - 700 calories per week. Fortunately, users of these devices typically have a downward trend of caloric intake and upward trend of activity, which generally makes them "work". But, assuming if it works for one person, it should work the same for everyone is a fallacy.

    No. No, it isn't. You're not understanding again.

    If I sit on my butt all day, my BMR would be over 70% of my calories burned. If I work out a lot, it'll be 45% or less. Same person. Two days apart.

    And depending on ALL THOSE FACTORS THAT YOU LIST TOGETHER, this MIGHT fluctuate by as much as 20%. That's a crazy-high fluctuation--that's including all kinds of extreme medical conditions on either end.

    Between two "normal" people, it will settle out to less than a +/-5% variation, even with the kinds of conditions that most people have.

    Body composition? Come on. A pound of muscle burns 7-13 calories, depending on the study. A pound of fat 2-4. If you change out 30lbs of fat for muscle, you might get 300 calories a day difference. AT THE MOST. And that's a serious, serious bodybuilder versus a guy whose weightlifting consists of picking up a 6-pack (because I'm assuming a guy of the same weight with 30lbs of muscle that could be gained). This is an extreme example, with the most generous numbers possible used.

    Your HRM is probably WAY off because you don't have VOmax set. Lots of people make this mistake. Effort does burn a few more calories...but sadly really not much. The web-based calculator is going to be way more accurate for a ride unless you're using a GPS-based system that takes elevation change into account.
  • MamaBirdBoss
    MamaBirdBoss Posts: 1,516 Member
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    rosebette wrote: »
    I'm having the reverse problem, I think. I'm wondering whether the Fitbit is underestimating what I'm burning. Today I took a 30 minute walk (1 mile and a half), did an hour yoga class (average to gentle, not power), laundry, some light yard work -- raking and seeding for about half an hour, and another 20 minute walk (about a mile) before supper. Before lunch but after my 30 minute walk, I got around 60 exercise calories from my MFP adjustment, but by the end of the day, it was down to 13 -- calories got taken away, even though I wasn't exactly a couch potato. Right now, my total calories used from my fitbit, which I assume is my TDEE is only 1245 calories. I know I'm small (5'1.5") and over 50 years old, but still this doesn't seem like much for that amount of activity.

    You get more credit for activity if you're older. Not sure why.

    And the calories taken away...um, kinda infuriates me. LOL. It assumes I shouldn't sleep 8 hours a day....
  • MamaBirdBoss
    MamaBirdBoss Posts: 1,516 Member
    edited June 2015
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    Oh, and I looked it up...clocked 20,000 steps two days ago.

    "Fitbit calorie adjustment - 314"

    But clearly, I'm just lazy. :P Any normal person would be walking 60,000 steps a day, right?
  • Christine_72
    Christine_72 Posts: 16,049 Member
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    @MamaBirdBoss your figures are making my head hurt!
    Something just isn't adding up... It shouldn't be this hard
  • NobodyPutsAmyInTheCorner
    NobodyPutsAmyInTheCorner Posts: 1,018 Member
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    Orphia wrote: »
    Merkavar wrote: »
    Orphia wrote: »
    I have to walk around 21,000 steps or over 10 miles to get to that magical 1000 calorie burn. I've been trusting my fitbit, and so far so good.

    10,000 steps with my iPhone 6 Health app gets me a bit less than 2,000 kilojoules.

    Somebody help me with the maths!

    And kudos and amazement @christinev297 for using calories/miles as a fellow Australian. I've barely got the hang of pounds. :)

    I hope I'm not wrong here but 2.2 pound to a kg. 4.18kj to cal and 1.6km to a mile are the conversions I use. Might not be 100% but close enough I think.

    So is calories another one of those measurements that are used by the U.S. and like 3 other countries that are so small you can't even see them on a world map printed on A3 size paper?

    :smiley:

    Hahahaha, like Fahrenheit and the Imperial system! I'm not sure, but I've found that quite a lot of products only show the kilojoule count here in Australia. I'd like to know if calories are the default in any other countries.

    We use calories here in the UK. Kilojoules... Wut? Ha. I'm a calorie girl.
  • NobodyPutsAmyInTheCorner
    NobodyPutsAmyInTheCorner Posts: 1,018 Member
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    My Fitbit Charge HR usually gives me around 300-400 extra calories a day when I do around 13000 steps. I'm set on lightly active as I walk everywhere and have a job where I'm on my feet most of the day. Most days I hit 10k steps and am often above but I still get like I say 300 or so extra calories. I don't use them though unless I'm starving marvin. lol
  • Christine_72
    Christine_72 Posts: 16,049 Member
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    I've had a slack day today,, spent most of it lying in a dentist chair blaaahhhh :cold_sweat:

    Thus far I've done 10,065 steps, fitbit has given me 348 extra calories.