Soooo...why does MFP overestimate calories burned? (if that's even true)

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myszka0611
myszka0611 Posts: 17 Member
edited April 2016 in Health and Weight Loss
I've read multiple threads where a delighted So-and-So would say "I exercised an extra X number of minutes, and was under my calorie goal, so I treated myself to <insert yummy thing here>, woo-hoo!" , only to see later in the thread some Debbie Downer piping in with, "Well, you KNOW that MFP overestimates calories burned, don't you, so I want you to know that you just totally ruined the three years you've been dieting because of that <insert yummy thing here> you ate. You only should have eaten 1/2 of it, you fool, or maybe just inhaled the aroma. Goodness, EVERYONE on here knows that but you, apparently". And then storms off in a huff...

So my question is....why doesn't MFP tweak their "exercise calories burned algorithm" if that's the case? Maybe even go to the other extreme by UNDERestimating exercise calories burned, so us chub-chubs might burn even more calories without even knowing it?
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Replies

  • MissusMoon
    MissusMoon Posts: 1,900 Member
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    I haven't found that they are over-estimating with the exercise I'm getting. I double check the actual machines I'm using when I enter my weight and look them up on other sites...pretty close in my case.

    I do see people saying they over-estimate everywhere here, though.
  • panda4153
    panda4153 Posts: 417 Member
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    At the end of the day everything is an estimate. For a very long time I lost just fine at the rate I put into MFP without food scales, using the MFP or machine estimate etc. I ate back every single calorie. I think what can happen though is that as you get closer to your goal weight, your margin of error becomes smaller, so we start to see threads asking how come I am not losing and then the "you may be overestimating" comes up.
  • AnnPT77
    AnnPT77 Posts: 32,850 Member
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    Estimating is estimating. They do the best they can. Because the database estimate may be high, some people choose to eat back only part of it, and take the rest of the calories (if there are any in real life) as an add-on to their deficit. But the database estimates could be low, too. I think most people don't feel the need to take precautions because of that.

    Think about it: Mostly, the problem is that the estimates can't be exact.

    If the data base has a good estimate for 1 hour on the elliptical for a 200-pound person, it's an average over many observations, i.e. many different people.

    But when you get down to one person (which is what we care about in our diaries), a 200-pound person sprinting on the elliptical burns more calories than a 200-person swinging along lackadaisically. Probably a fit 200-pound person burns fewer calories than an unfit one at the same speed (because of efficiency and adaptation). The person may be using their arms a lot, or not much. It varies.

    The database estimates are science-based. But they're basic (they don't ask you how many hills were on your walk, they have a range of walking speeds in one entry, etc.) - though you can find specialized calculators on the web that use more inputs specific to particular activities, so can estimate more closely (still an estimate). Or you can use a device (Fitbit, HRM, etc.) to get a more personalized estimate (still an estimate).

    If you care a lot, you can get a better and more personalized estimate. If you don't want to be bothered, you can just use the database, and adjust for the risk you care most about - the risk that the burn is over-estimated - by not eating all the calories back.

    Personally, I work a little harder on making better estimates, then eat all the calories back. If my weight loss rate suffered as a consequence, I'd change my approach. But it worked.
  • myszka0611
    myszka0611 Posts: 17 Member
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    3dogsrunning wrote: »
    You may find this blog helpful
    http://www.myfitnesspal.com/blog/Azdak/view/estimating-calories-activity-databases-198041

    MFP uses the Compendium of Physical Activities as many sources do.

    Peronally, I hate the MFP database bashing. Is it perfect? No. It is useful if used with common sense. Some entries will be better than others.



    There is not perfect way (outside of a lab) to know calories burned. Every method has it's strengths and weaknesses.

    Thank you! That explains it nicely!
  • Orphia
    Orphia Posts: 7,097 Member
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    LazSommer wrote: »
    If they under estimate and some moron ends up malnourished because they can't figure it out "MUH calorie intake!", they will likely get a lawsuit because God bless America.

    Quoting for the awesome on-targetness.
  • Colorscheme
    Colorscheme Posts: 1,179 Member
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    MFP uses a formula. It's an estimate. I rely on my fitness tracker, but I understand not everyone has one or can afford one.
  • scolaris
    scolaris Posts: 2,145 Member
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    It's just an estimate. That's why. When I plugged my activities into MFP it always gave me a generic 500-600 calories for Zumba which I knew had to be high because I had some orthopedic stuff resolving & I knew the intensity level I was dancing at was slightly lower. My Fitbit HR confirms that I burn anywhere between about 375 to 435 from week to week depending on how my knee feels, how well I know the routines, etc.
  • senennieves
    senennieves Posts: 106 Member
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    I have my fit bit surge synced in to my MFP account , and i have not been able to check my weight, but my pants are feeling loser and i have tighten my belt a little, xd.
  • nuttynanners
    nuttynanners Posts: 249 Member
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    It all depends on your height, weight, age, level of exertion, the moon's gravitational pull on earth, etc. Okay the last part was a joke...

    But I like using my own HRM to get a more personalized estimation. It's still an estimation, though! You really can't rely on ANY machine or computer program to give you a totally accurate number, because it's impossible to know for sure.
  • Nicklebee93
    Nicklebee93 Posts: 316 Member
    edited April 2016
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    I tend to see people that are extremely helpful and nice on these forums. Most people do recommend to only eat about 50-75% of exercise calories back because MFP can only give you an estimate.

    How does MFP know your intensity? If you followed a modified version, vs the normal or the higher version? The only way to accurately log those calories is if you do the formula yourself.

    I have a workout video that does burpees. One version is a slow, one leg comes in at a time modify. The other is a regular but without the jump in the end. And the last one is a full burpee. Depending which one i do, well then i'm burning more or less. How many did i do in that minute? Too many variables and that's why MFP sometimes lacks in the calorie burns category..
  • Pinkvela
    Pinkvela Posts: 21 Member
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    I always underestimate the exercise calories and overestimate the food amount. I remember seeing a show where they tested a professional athlete on a stationary bicycle exactly for the purpose of "numbers" accuracy and there was a discrepancy between what the machine recorded and the way the lab recorded it (complete with oxygen/type mask thing and electrodes and what have you). Lesson was: It takes a lot to even burn a few calories and it has to be sustained effort at a certain intensity. My rule: If I don't break a ( big) sweat then it probably hasn't amounted to much.
  • Psychgrrl
    Psychgrrl Posts: 3,177 Member
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    I figured it was the same reasons cardio machines over-estimate for people--because the burns are often based on a lbf, muscular (I.e. In shape) 20-something male. Even when adjusted for sex, age, weight, that basis can still make them off. Especially if there's no hrm input to determine actual intensity.

    Whenever I compare machine calories burned to my hrm calories burned, it's about 200-250 less for an hour on a Pre-Cor for the hrm. If I input into MFP, I have to lower the time I worked out to get the hrm calories out number, because for me, MFP over-estimates. I'm a small female.

    If someone is bigger, 250-300, I'd guess they may be burning more than the machine norm.

    The programming required for automatic customization of calories burned for each member based on their stats might not be feasible for a free site.
  • MelodyandBarbells
    MelodyandBarbells Posts: 7,725 Member
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    A lot of it is results based, where people eat back a certain percentage of their exercise calories and lose the expected amount of weight per week. Now could this discrepancy be due to inaccurate food logging? Absolutely. But adjusting down the exercise calories can be a great way to compensate for that and still get good results.
  • jandsstevenson887
    jandsstevenson887 Posts: 296 Member
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    I actually think MFP underestimates the workouts I enter based on other data
  • sijomial
    sijomial Posts: 19,811 Member
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    You don't make an estimate more accurate by reducing it by a random percentage.

    There certainly are some estimates which seem far too generous but there's also many that are entirely reasonable and use industry standard formulae.

    The application of common sense and then willingness to adjust based on results will get people where they need to be.

    For most focussing their energy (no pun intended) on their food logging accuracy will make a far bigger difference.

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