MFP calorie estimate / eating back calories - miscalculation

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steve2kay
steve2kay Posts: 194 Member
in Fitness and Exercise
This is all rounded to make it easy to do the maths.

If my TDEE is 2400 calories. I assume I burn more calories in my waking hours, so let's assume I burn 50 calories an hour during the 12 hours I'm asleep and 150 calories an hour during the 12 hours I'm awake.

I'm trying to lose weight so am eating 2000 calories a day.

So if I walk for 60 minutes and burn 400 calories - that's only actually 250 more than I would have burnt anyway. If I eat back 400 calories that would take my daily intake to 2150 instead of 2000 and therefore slow my weight loss?

I think maybe I should take 150 calories an hour off any that MFP add on for exercise I've done.

I know the numbers aren't exact, but you get the point - does this make sense?

Replies

  • ScottGut
    ScottGut Posts: 10 Member
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    "during the 12 hours I'm asleep" WHAT!?
  • steve2kay
    steve2kay Posts: 194 Member
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    my brain couldn't do the maths for 8 hours of sleeping, so I just went with 12. Maybe if I got 12 hours sleep I could do more complicated maths.
  • KMMRN
    KMMRN Posts: 104 Member
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    Steve.....I have had the same thoughts for years, I think you're right! I find when I make the adjustments you suggest, I can predict exactly what my weight loss will be.
  • samammay
    samammay Posts: 468
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    I dont know how MFP handles it but I have a fitbit and when I am logging other exercise either through MFP or Runkeeper, it stops counting my being alive burn/walking/movement to compensate.
  • jollyjoe321
    jollyjoe321 Posts: 529 Member
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    Ah, you mean you think MFP doesn't consider that how many calories are burnt during exercise should be the difference between sitting still/average activity, and working out?
  • floareaciprian
    floareaciprian Posts: 46 Member
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    GOAL = FOOD - EXCERCISE.
  • jacksonpt
    jacksonpt Posts: 10,413 Member
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    If you're basing your calorie goal on TDEE, you don't eat back exercise cals.
  • cwolfman13
    cwolfman13 Posts: 41,874 Member
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    MFP doesn't use your TDEE, MfP only uses your NEAT and your exercise is accounted for after the fact...this is why you log and eat back exercise calories burned. If you're using TDEE, then you don't eat back exercise calories as they are accounted for before the fact in your activity level.

    Also, yes...you would need to subtract BMR calories from whatever burn you're getting (data bases can be wildly inaccurate in the first place) which is what I used to do with my HRM burned calories as that number includes both calories I burned working out plus calories I would have burned watching t.v. for that same time. That said, don't over think the sleeping or awake part...just divide your BMR by 24 hours and go form there.
  • alanlmarshall
    alanlmarshall Posts: 587 Member
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    The calorie estimates are inconsistent and from various sources anyway.
  • TeaBea
    TeaBea Posts: 14,517 Member
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    This is all rounded to make it easy to do the maths.

    If my TDEE is 2400 calories. I assume I burn more calories in my waking hours, so let's assume I burn 50 calories an hour during the 12 hours I'm asleep and 150 calories an hour during the 12 hours I'm awake.

    I'm trying to lose weight so am eating 2000 calories a day.

    So if I walk for 60 minutes and burn 400 calories - that's only actually 250 more than I would have burnt anyway. If I eat back 400 calories that would take my daily intake to 2150 instead of 2000 and therefore slow my weight loss?

    I think maybe I should take 150 calories an hour off any that MFP add on for exercise I've done.

    I know the numbers aren't exact, but you get the point - does this make sense?

    Yes - there is some redundancy in MFPs numbers & my HRMs for that matter.

    BMR - these would be your sleeping calories

    BMR + Sedentary activity level .... these are hours at a desk job.

    Then there are the calories added for your workout ....MFP would have me add 100% of my HRM calories (as MFP numbers are even higher) ... but you're right, if I add 100% of my HRM, I technically should substract out the BMR number .....for the same number of minutes as my workout. My workouts are never huge, so this is not much of a factor for me.

    But as jacksonpt points out ..... a TDEE would already include exercise ..... so no need to log exercise calories and eat them back. If you wanted an exercise "log" of sorts .......you can over ride calories burns to 1.
  • MrsFowler1069
    MrsFowler1069 Posts: 657 Member
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    "during the 12 hours I'm asleep" WHAT!?
    my brain couldn't do the maths for 8 hours of sleeping, so I just went with 12. Maybe if I got 12 hours sleep I could do more complicated maths.

    I love this. :)
  • meerkat70
    meerkat70 Posts: 4,616 Member
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    you take your base calories out. there was a thread from mike about this.

    eat back your cals less your base cals. most hrms also include base cals in their burn estimates.

    given this and allowing about 10% error in mfp estimates, if you take 10-20% off the mfp numbers you should be ok.
  • nelinelineli
    nelinelineli Posts: 330 Member
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    This is all rounded to make it easy to do the maths.

    If my TDEE is 2400 calories. I assume I burn more calories in my waking hours, so let's assume I burn 50 calories an hour during the 12 hours I'm asleep and 150 calories an hour during the 12 hours I'm awake.

    I'm trying to lose weight so am eating 2000 calories a day.

    So if I walk for 60 minutes and burn 400 calories - that's only actually 250 more than I would have burnt anyway. If I eat back 400 calories that would take my daily intake to 2150 instead of 2000 and therefore slow my weight loss?

    I think maybe I should take 150 calories an hour off any that MFP add on for exercise I've done.

    I know the numbers aren't exact, but you get the point - does this make sense?

    Yes you are absolutely right about this, and it's been a caveat for a long time. Same issue with people using HRMs for workouts.
    It can be problematic at low deficits, but overall people underestimate their TDEE anyway so it sort of evens out.
    But yes you're absolutely right about the redundancy.

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