Calorie results between my device and MFP differ

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fotoman515
fotoman515 Posts: 14 Member
in Fitness and Exercise
I wear a Polar A370 exercise and heart rate monitor during exercise. When I sync my results to MFP I notice that the caloric results are less in MFP then what resulted from my exercise as compiled by Polar. Why is that and is there a way to correct it?

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  • yirara
    yirara Posts: 9,389 Member
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    It’s likely that your device displays gross exercise calories: the energy your body would burn anyway to run your organs plus the ecercise calories. The first is already part of what mfp gives you. If all calories were transferred you’d be double dipping
  • Lietchi
    Lietchi Posts: 6,109 Member
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    yirara wrote: »
    It’s likely that your device displays gross exercise calories: the energy your body would burn anyway to run your organs plus the ecercise calories. The first is already part of what mfp gives you. If all calories were transferred you’d be double dipping

    I will second that. I used to have a Polar device and I seem to remember it shows the gross calorie burn.
  • fotoman515
    fotoman515 Posts: 14 Member
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    So, here is what is happening. During today's cycling my A370 indicated I burned 299 kcal. but MFP recorded 286. Now I'm not crying over 13 calories I'm just trying to understand why it's happening. If I check "show negative calories" then MFP adds what Yirara indicated. I've attached a couple of screen shots to show you what's happening.tl85lp0mftwo.png
    b0nvgg0xwb6m.png
  • yirara
    yirara Posts: 9,389 Member
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    Negative calorie adjustment is something completely different and related to the activity level you've chosen. I didn't know this works for other things than steps, but anyway... if you've chosen sedentary and you walk a lot more steps than qualify for sedentary you get more calories. If you've chosen super active, and you only walk 1000 steps you lose calories. But um... no idea
  • Lietchi
    Lietchi Posts: 6,109 Member
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    fotoman515 wrote: »
    So, here is what is happening. During today's cycling my A370 indicated I burned 299 kcal. but MFP recorded 286. Now I'm not crying over 13 calories I'm just trying to understand why it's happening. If I check "show negative calories" then MFP adds what Yirara indicated. I've attached a couple of screen shots to show you what's happening.tl85lp0mftwo.png
    b0nvgg0xwb6m.png

    As Yirara said, your calorie adjustment is something different.
    MFP compares the total calorie burn between the activity level you selected on MFP (which does not include exercise!) plus calories burned by exercise on the one hand and the total calorie burn given by Polar on the other hand. So any exercise you do will be added on both sides.

    An example with some invented numbers:
    - you chose the activity level setting 'lightly active' but you were sedentary (only 2000 steps) except for your cycling session.
    - your cycling burned 500 calories
    - not counting your exercise you burned 2000 calories instead of the 2250 calories MFP thinks you would burn when being lightly active. Including your exercise MFP thinks you should have burned 2750 (2250 +500) calories, but Polar says you only burned 2500 -> MFP gives you a negative calorie adjustment of 250 calories
  • fotoman515
    fotoman515 Posts: 14 Member
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    I guess I'll just live with it.
  • NorthCascades
    NorthCascades Posts: 10,970 Member
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    fotoman515 wrote: »
    So, here is what is happening. During today's cycling my A370 indicated I burned 299 kcal. but MFP recorded 286. Now I'm not crying over 13 calories I'm just trying to understand why it's happening. If I check "show negative calories" then MFP adds what Yirara indicated. I've attached a couple of screen shots to show you what's happening.tl85lp0mftwo.png
    b0nvgg0xwb6m.png

    Because neither one knows the truth and they're both guessing. You know the contest where everybody has to guess how many jelly beans are in a glass jar and everybody has a different number? Same thing here. Educated guesses.
  • heybales
    heybales Posts: 18,842 Member
    edited May 2021
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    fotoman515 wrote: »
    I guess I'll just live with it.

    Just be clear - nothing much to "live with" as if it's broken - it's working right.

    For the day, your exercise may have added on 299 calories, but you were less active outside the exercise and so only got 286 more.

    Shoot - that's minor.

    I've had days of big long bike ride, and due to all the other time being much less than sedentary, had a -200
    to 400 adjustment.

    So the workout added 1400, my being more than lazy otherwise removed 400.
    My net gain for the day was 1000 more than sedentary.

    And as should be correct, the calorie deficit starts at the total burned.

    If you took that day at the end, looked at the estimated daily burn on the tracker, subtracted your deficit that MFP uses, it'll probably match your final MPF eating goal.
    I say probably, because there are deficits too big for the math to workout unless you do exercise or are more active.

    Oh, the page you need is the Exercise Diary, not Food Diary.
    Line about Polar Adjustment - click on the blue I for more Info.
  • yirara
    yirara Posts: 9,389 Member
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    And finally: keep in mind that what your tracker or MFP shows you for your exercise is not a fact. it's a guess based on average population data, how well your heartrate matches 220-age or whatever custom HR you've chosen, and how well the developers have implemented calorie estimates for various types of exercise. It's a guess that might fit you, but might also be completely off.

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