Confused by how MFP calculates calories burned by exercise

weedspot
weedspot Posts: 29 Member
in Health and Weight Loss
Hi!

My 45-60min arm day workout allegedly burns 500 calories. I checked online and most 60 minutes workout involving weights only burn 200-300 calories. I don’t even lift that heavy.

So my question is: how accurate is MFP when it comes to calories burned by exercise ? I made sure to put in every reps and the weight of my dumbbells for each exercise.

Replies

  • charmmeth
    charmmeth Posts: 936 Member
    The general consensus here on the forum is that many of the calorie estimates for exercise in the mfp database are wildly over inflated. I now calculate my own estimate based on the METS value of whatever I am doing and enter a new activity with a more reasonable estimate. I do roughly the same things in any given week, so it did not take long.

    The tools I use are: http://prevention.sph.sc.edu/tools/docs/documents_compendium.pdf
    and http://ergo.human.cornell.edu/MetsCaloriesCalculator/MetsCaloriesCalculator.htm.

    Others will use a HR tracker or similar to generate calorie values which they can then enter directly.
  • weedspot
    weedspot Posts: 29 Member
    charmmeth wrote: »
    The general consensus here on the forum is that many of the calorie estimates for exercise in the mfp database are wildly over inflated. I now calculate my own estimate based on the METS value of whatever I am doing and enter a new activity with a more reasonable estimate. I do roughly the same things in any given week, so it did not take long.

    The tools I use are: http://prevention.sph.sc.edu/tools/docs/documents_compendium.pdf
    and http://ergo.human.cornell.edu/MetsCaloriesCalculator/MetsCaloriesCalculator.htm.

    Others will use a HR tracker or similar to generate calorie values which they can then enter directly.

    Thanks! I’ll check all that out
    I knew something felt weird with their calculations
  • cppeace
    cppeace Posts: 764 Member
    They calculate on weight, age, and what you chose for activity level. They will go on averages for those things x your time entered. We are all widely different. For examples. If I go on what mfp says my walks burn 200 calories instead of 300 or more. Mfp can't know how short my step radius is or how hilly the path. A heart rate monitor is generally the most accurate for most.
  • AnnPT77
    AnnPT77 Posts: 34,226 Member
    After you using an MFP "workout program"? Those seem to me to dramatically over estimate strength exercise calories.

    If, instead, you use the MFP exercise database, and pick "cardiovascular exercise" then "strength training", and put in the wall clock time of the workout (including between set rests), you should get a much more reasonable estimate.

    I get something under 150 calories per hour, which is much more reasonable for a strength workout. (The estimate will vary with bodyweight; I'm 128 pounds,.)

    I don't prefer the exercise database to estimate all exercises, but believe it's reasonable for strength training.
  • sijomial
    sijomial Posts: 19,809 Member
    It's more likely the way you are logging your exercise that is the problem.
    A screenshot of how you logged it would help as your diary is private.

    What you found online is probably coming from the same source as the CV diary / strength training option here on MyFitnessPal that Ann mentions above - The Compendium of Physical Activty.

    There is a generic problem of the database being gross cals instead of net but with hundreds and hundreds of different exercises in the database they aren't all inaccurate let alone inaccurate by the same percentage for an individual.
  • sijomial
    sijomial Posts: 19,809 Member
    edited September 2020
    cppeace wrote: »
    They calculate on weight, age, and what you chose for activity level. They will go on averages for those things x your time entered. We are all widely different. For examples. If I go on what mfp says my walks burn 200 calories instead of 300 or more. Mfp can't know how short my step radius is or how hilly the path. A heart rate monitor is generally the most accurate for most.

    @cppeace

    A heart rate monitor is a dreadful way to estimate calories burned during strength training, primarily as it's not an aerobic activity.
    They are also very poor for cardio intervals and poor for people who happen to have a non-average exercise heart rate - including but not limited to unfit people.
    There simply isn't a direct relationship between heartbeats and energy expended.

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