Fitness trackers and calorie counting

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Cronniss
Cronniss Posts: 108 Member
in Fitness and Exercise
So I just got my Polar A300 and I'm loving it. It tracks everything I need it to, it does everything I want it to. But there's something I'm wondering about.

I've been reading in the forums that people reduce the calorie count from their fitness/activity tracker by 80% (on average). Why is this? And should this be done for every fitness tracker? I use the HRM when I workout, so shouldn't that make the tracker more accurate?

Now I don't eat back all of my burnt up calories. In fact, I don't even reach my daily calorie count....at least for now. So while this may not affect me at the moment, it is future knowledge that I will need to maintain my weight properly.

I appreciate any information that anyone can provide on this.

Replies

  • WaterBunnie
    WaterBunnie Posts: 1,370 Member
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    I use a FitBit One but I've lost weight well eating all of mine. Maybe it's to allow for inaccuracies in food logging?
  • tibby531
    tibby531 Posts: 717 Member
    edited June 2015
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    I would guess it's because your exercise calories burned includes your BMR burn, also. I have a friend that logs calorie amounts as her BMR. I try to just leave mine on the board. example: I burn 70 calories an hour just breathing. so for every hour I exercise, I try to leave 70 calories open on my diary.
  • editorgrrl
    editorgrrl Posts: 7,060 Member
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    WaterBunnie wrote: »
    I use a FitBit One but I've lost weight well eating all of mine. Maybe it's to allow for inaccuracies in food logging?

    ^This. Some people find it easier to eat back a percentage of their exercise calories than to learn to log everything they eat & drink accurately & honestly. Both accomplish the same goal—ensuring you're eating fewer calories than you burn.

    The only way to gauge the accuracy of an activity tracker or heart rate monitor is to trust it for several weeks then reevaluate your progress. I eat back all my Fitbit adjustments, and I lost the weight & have maintained for almost a year. Food is fuel, and we should all be looking for the maximum number of calories at which we lose weight—never the minimum.
  • LivingtheLeanDream
    LivingtheLeanDream Posts: 13,342 Member
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    80%? more like they over estimate from 5-10% in my experience, but for everyone that will differ, logging inaccuracies contribute as well ...but overall its a great gadget to help keep us on track and motivated - enjoy :smile:
  • jgnatca
    jgnatca Posts: 14,464 Member
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    I read an article where the author pointed out that most fitness trackers also include your basal metabolic rate (burn) during exercise. In my case, I burn 1,650 calories a day just living. So caution should be taken adding exercise calories.
  • dnagirl712
    dnagirl712 Posts: 10 Member
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    For me it depends on what kind of activities I'm doing. When I'm getting my steps/calorie burn primarily by walking, I don't make up the entire deficit. On days I run more than 3 miles, I will usually eat all of those calories back or I will feel very tired the next day. For me, it's been about trial and error listening to my body and what works best for feeling best.
  • editorgrrl
    editorgrrl Posts: 7,060 Member
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    jgnatca wrote: »
    I read an article where the author pointed out that most fitness trackers also include your basal metabolic rate (burn) during exercise. In my case, I burn 1,650 calories a day just living. So caution should be taken adding exercise calories.

    Connecting an activity tracker (like Fitbit) to MFP is entirely different than using MFP alone. MFP "trains" you to think, if I run on the treadmill, I'll immediately "earn" more calories to eat. Your Fitbit burn is TDEE, the number of calories to maintain your current weight. Your default MFP calorie goal is activity level minus deficit. When you connect your accounts, MFP looks at your Fitbit burn and adjusts your calorie goal accordingly.

    If (and only if) you enable negative calorie adjustments in your MFP diary settings, eating back your Fitbit adjustments means you're eating TDEE minus deficit.* You can learn more in the Fitbit Users group http://community.myfitnesspal.com/en/group/1290-fitbit-users

    *But as @WaterBunnie said above, you still have to log everything you eat & drink accurately & honestly.
  • Docbanana2002
    Docbanana2002 Posts: 357 Member
    edited June 2015
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    A lot of people don't eat back all their exercise calories because of concerns that the numbers are overestimated a bit and that they are actually cutting into their calorie deficit.

    When I started using a fitbit, I kept data on my actual weight loss over a 2 month period and my predicted weight loss based on food logging + calorie burn estimates (by adding up my calorie deficit for that period and dividing by 3500 calories per pound). I discovered that I was actually losing about 10% faster than my data would predict. I continue to check periodically using new data (I've used fitbit since last September) and the data still tell me that I'm very slightly off in a way that means that I am UNDERestimating my calorie burns (or my food intake, I'm not sure which). For that reason I trust my fitbit burn estimates are accurate and will eat back all the calories. I could actually eat back a few extra given the direction of my error but I choose to ignore that and just keep that as a little buffer zone. (When I finish losing weight I might have to address this to find where maintenance REALLY is, but it appears to be a little bit higher than where MFP says it is.)
  • Cronniss
    Cronniss Posts: 108 Member
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    I thank you all for your contribution! Basically I'm just going to have to wait & see, and balance it out to my personal needs :D I don't even know what my metabolism is like right now as I'm still "in flux." (Still loosing weight at a good pace, and I have increased activity.)
    dnagirl712 wrote: »
    For me it depends on what kind of activities I'm doing. When I'm getting my steps/calorie burn primarily by walking, I don't make up the entire deficit. On days I run more than 3 miles, I will usually eat all of those calories back or I will feel very tired the next day. For me, it's been about trial and error listening to my body and what works best for feeling best.

    My activity is broken up in the day. First thing in the morning after I wake up is a brisk 20 minute walk with the dog. Then right before lunch I have a 40-45 minute aerobic workout.

    Like I said, I don't even reach my calorie goal MFP has set for me (which it recently recalculated for me to be 2,000 calories....down from 2,070); but I'm not tired or run down throughout the day. In fact, I'm feeling more energized and I'm having a hard time settling down to go to sleep. (And I'm even on medication that's supposed to help with that. :p )

    And it's not like I'm starving myself. I take in on average between 1,700 and 1,900 calories a day. When I hit my goal weight I may just need to find more calorie dense foods. ;)
  • tlfoth
    tlfoth Posts: 16 Member
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    I use my tracker for motivation and add my exercise manually. Sometimes trackers aren't very accurate. I have fribromyalgia and if I don't move the arm my tracker is on it won't count it so I just use it more for motivational purposes to get off my butt.
  • ElizabethKalmbach
    ElizabethKalmbach Posts: 1,416 Member
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    My fitbit calorie burn estimates may be high, but it also doesn't log ALL my steps as accurately as it could. It seems to log about 80% of my steps when I'm messing around with my phone, touching railings, carrying things, etc. I eat back all the suggested calories and still lose weight - slightly faster than predicted at that.
  • ScubaSteve1962
    ScubaSteve1962 Posts: 609 Member
    edited June 2015
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    tibby531 wrote: »
    I would guess it's because your exercise calories burned includes your BMR burn, also. I have a friend that logs calorie amounts as her BMR. I try to just leave mine on the board. example: I burn 70 calories an hour just breathing. so for every hour I exercise, I try to leave 70 calories open on my diary.

    polar separates your exercise and activity calories, from your BMR calories. and MFP only gives you credit for actual exercise calories from Polar, which you will only get when wearing the sensor, and recording.

    To the poster, I have a V800, and I don't adjust, I let MFP adjust them. If I don't work out I may get a negative adjustment, and when I do, I usually get a positive adjustment.

    I'm suspecting your HRM is like mine, it will only record your heart rate when you're wearing the sensor, and you tell it to with the profile that you are using. It calculates your BMR age, weight, and by what was found during the tests. That's why as you loose weight, you have to change your settings and test again.
  • professionalHobbyist
    professionalHobbyist Posts: 1,316 Member
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    Your Polar HRM knows your heart beats as part of just being alive

    So...

    It isn't like when you exercise while wearing it the BPM is calculated as pure total additional calories

    There is a compensation. I asked that at the gym when I got it and did the Polar body fitness age test thing. It was all pretty informative. Maybe your gym has that. The trainer was helpful as well.

    I found that my main accuracy issue was not having a food scale.

    Many others have pointed out that accurate logging in if all calories, coffee creamer, all that... It all matters.

    I know some talk about the conversion of certain exercises to calorie counts having accuracy issues. I don't really know.

    I exercise to a heart rate target. I don't count or enter calories related to weight lifting. I circuit train to a heart rate zone.

    And I always lose a little ahead of the pounds predicted by my food log now that I use a good scale and count every little thing!

    A HRM is a great tool and general reference. I do jumping jacks between sets of lifting some days to get my heart rate up.

    I do eat back some of the step related calories I burn off. If I have 400 burnt, and I want another grilled chicken fajita... That baby is going down!

    Just not always.

    It has gotten to where losing is fun. I'm excited to see this stuff work!

    It is awesome to see you are getting all over the fitness lifestyle OP. Using the tools available to help you get there.

    It sounds like you are gonna make it happen!

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