Net versus Gross calorie burn...

Kara_xxx
Kara_xxx Posts: 635 Member
Does anyone subtract the calories that you would normally burn just to support your RMR??

So far I haven't but this article made me think??

>>>> cut & paste <<<<

A Common Mistake Related to Net and Gross Calorie Burn
Now that you understand the meaning of net and gross calorie burn, you should be able to avoid one of the most common mistakes that people make when tracking their calorie burn, illustrated by the following scenario:

Let's suppose that you have decided to start a weight loss program to lose 10 pounds over 20 weeks (this is a weight loss rate of 1 pound every 2 weeks). Before starting this weight loss program you performed no regular exercise and you were neither gaining nor losing weight, so you must have been burning exactly the same number of calories that you were consuming. Rather than modify your diet to lose weight, you decide to continue to consume the same amount of calories while increasing your calorie burn through daily exercise. Since there are roughly 3,500 calories in one pound of fat, you decide to run on a treadmill every day until you've burned 250 calories according to the treadmill's calorie burn calculator. 250 calories per day will add up to 3,500 calories, or about 1 pound of fat, every 2 weeks, because 250 x 14 = 3,500. So, according to this strategy you should expect to lose about 1 pound of fat every 2 weeks, right? Wrong.

The mistake here, which is extremely common, is that a typical calorie burn calculator on a treadmill provides gross calorie burn estimates. If you run on a treadmill (one that provides gross calorie burn estimates) until it says that you have burned 250 calories, it is not lying, you have in fact burned 250 calories, but a substantial portion of those calories were burned to support your RMR and so they would have been burned anyway, even if you were at home sitting on the couch. They are not calories that can be counted toward weight loss in your overall caloric balance, because they were already being burned before you started your weight loss program (remember, calories are always being burned to support your RMR, no matter what you are doing) and were and are balanced out by your unmodified calorie consumption. You need to figure out what your net calorie burn was on the treadmill and count only this number toward your weight loss goal.

For example, to use some actual numbers, let's suppose that you are a 30 year old, 125 lb, 5'5" tall woman. With these measurements you would have a RMR of approximately 1500 calories per day. After 30 minutes of running, at about 5.2 miles per hour, a treadmill calorie burn calculator (one that provides gross calorie burn estimates) will show that you have burned about 250 calories. However, since your RMR is 1500 calories per day, while running for 30 minutes you burned roughly 30 calories to support your RMR. Therefore, your net calorie burn while running on the treadmill is about 250 - 30 = 220 calories. As a result, you have a caloric balance deficit of 220 calories per day, instead of your originally anticipated 250 calories per day, and you should expect to lose roughly 8.8 pounds over the course of 20 weeks, instead of the 10 pounds that you were hoping for.

>>>>

Anyone?

Are the scores on the database net or gross?

Replies

  • Nelski
    Nelski Posts: 1,607 Member
    Yes, when I log my calorie burn from exercise I subtract some for what I would have burned anyway.
  • alexandra0713
    alexandra0713 Posts: 41 Member
    The difference is generally going to be minimal, they are all estimates anyway. If I'm worried that the calorie burn doesn't add up based upon my level of exertion then I estimate lower by cutting off a few minutes of the activity time.
  • tadpole242
    tadpole242 Posts: 507 Member
    Yes, if I work out for an hour a day, I take off that hours basic calories. It's only about 80 for me, but no point in doubling up when it is simple to work out, and you can only burn one lot of calories at a time.
  • MonkeyBars
    MonkeyBars Posts: 266 Member
    ahem.... I love the data, but we're back to numbers...

    do we really know our BMR? how well can we predict our burn?

    how about adaption, when our bodies become more efficient and economise?

    How useful are measuring kcals in a positive/negative counting method?
    Are all kcals actually equal?

    I think you're trying to predict your weight loss.....

    Don't bother :)

    whooops
  • Qskim
    Qskim Posts: 1,145 Member
    ^^^ Agree, underestimate exercise and overestimate cals (if not weighing and cant find exact food on MFP)
  • kwin91
    kwin91 Posts: 128
    I don't use a HRM so I generally take some off with this other more correct calculator and then from that I minus about 50 so I underestimate anyways. It may not seem like much but at the end of the week, for me at least it adds up. So I do support the calories I would have burn just sitting and minus it from my gross burned calories.
  • Surely the best thing to do is only eat back the majority of your exercise cals - This should even out any errors in the calculations?
  • JonsConspiracy
    JonsConspiracy Posts: 4 Member
    The analysis is interesting and good to keep in the back of your mind. However, the difference between burning 220 calories or 250 calories, or losing 8.8 lbs vs 10 lbs, is minimal. Even if you did back out your RMR, I doubt you'd end up exactly at 10 lbs lost anyway.
  • JenaePavlak
    JenaePavlak Posts: 350 Member
    You will never be able to get exact numbers.. example: because I didn't eat the last bite of my food, I should subtract 10 calories?

    While this does make sense, I don't think anyone should be obsessed with the numbers especially that minimal.

    I never log my coffee (with cream), olive oil/butter, and I generalize most food.. (i put birdseye mixed veggies for almost any veggie I eat)..

    I want to learn how foods affect my body, not let numbers run my life... so don't take it too seriously and have fun!

    "Lift Heavy! Run Hard!" =D

    www.facebook.com/jenaesmithfitness -- Daily Motivation, Quotes, Pics, Etc. :)
  • onikonor
    onikonor Posts: 473 Member
    I subtract the calories but it doesn't really make much of a difference. Like 50 cal per hour?
  • tadpole242
    tadpole242 Posts: 507 Member
    ahem.... I love the data, but we're back to numbers...

    do we really know our BMR? how well can we predict our burn?

    how about adaption, when our bodies become more efficient and economise?

    How useful are measuring kcals in a positive/negative counting method?
    Are all kcals actually equal?

    I think you're trying to predict your weight loss.....

    Don't bother :)

    whooops
    All measurements are only a guess anyway, a mile, a 100, a pounds a kilo, when you get down to it why bother about doing anything, why not just give up, curl up, and sit in the dark corner and whimper.

    Not measuring didn’t work, or we’d not be here, so let’s try at least to do something different.
    You may come last, but at least you tried, you tried and failed but that is better than not trying at all.

    Your measurement may be inaccurate, but forget calories just call them units and treat them as such, eating less ‘X units’ will mean you weigh less ‘Y units’, or you can ‘z’ faster than before or for longer or with a greater intensity .
    You are an experiment of one, you choose your own goal, and you choose your own units for measuring that goal.
  • Kara_xxx
    Kara_xxx Posts: 635 Member
    Thanks for all the responses... I usually only eat back a proportion of my exercise calories rather than all...

    I guess at a 50 cals deduction per hour training session, even if you train every day that only comes to 350 cals over the week.
  • MonkeyBars
    MonkeyBars Posts: 266 Member
    [/quote]
    You are an experiment of one, you choose your own goal, and you choose your own units for measuring that goal.
    [/quote]

    best line... ever :)
  • It does make an important difference for low exertion long duration exercise. Let's say you take a leisurely three hour walk. Maybe you burn 690 calories. But net, you only burn 420 or so, depending on your size and all. So that's 270 phantom calories on your "safe to eat" list, provided the system calculated using gross. Again it's not a lot, but it is a six inch subway ham sandwich. You eat that and it's coming straight off your credit card so to speak.
  • I found out that after you stop exercising you're going to burn more bonus calories as your body winds down, maybe an extra 20 or so in the half hour after a hard workout (after an hour it seems to go back to genetically set levels, despite myths of all day metabolism raising). So more numbers for the game. You know. Geek pleasures.

    http://sportsmedicine.about.com/od/anatomyandphysiology/a/rmr.htm
  • l3rob
    l3rob Posts: 28 Member
    I saw that same article and it made me think about it too. It seems to me it depends on your current weight and goals. If you are at your ideal weight I agree with JenaeSmith, don't sweat it. If you are trying to lose weight and eating back your calories, you may want to pay a little more attention so that you are not beating your head against the wall trying to figure out why you may not be losing.
  • waldo56
    waldo56 Posts: 1,861 Member
    I think you're trying to predict your weight loss.....

    Don't bother :)

    It is actually not that hard to do.

    One principle of estimating that people do not generally do:
    When it comes to estimating a large system, the accuracy of the individual component is not all that important. What is more important is that you consistently estimate the same way, you strive to be the most correct (read NOT "safe"), approaching your estimate without bias, and you have a complete dataset, not skipping anything. The finer you break up components, the more accurate it becomes.

    When estimating a large system, if you avoid systemic error (such as trying to be "safe"), errors by and large cancel out. The bigger the system and the more components, the greater the accuracy, because of this error cancelling effect. I have done a lot of construction estimating in my life and it isn't that hard to have a very high degree of accuracy without spending much time on the accuracy of individual components, to the bottom line of the big picture it isn't important at all. As the system size increases, so does the accuracy; a day is more accurate than a meal, a week more accurate than a day, a month more accurate than a week. While a meal could be way off, by using the few principles above (completeness, no bias, consistency), a month should be at a fairly high degree of precision.

    For weight loss purposes, once you are producing a reasonably accurate daily estimate, adjust your calorie target to lose at a rate you desire if the rate doesn't match your predicted rate..

    While individual weigh ins may move around, you should be able to hit the weight loss rate of a moving average right on the nose if you do a good job at estimating (plus also realizing that plateaus happen because of too many or too few calories).

    Playing is safe with calories in or exercise calories may seem like a good idea, but it is poor estimating. If you are going to play it safe, instead do so with your daily calorie target, try to be right, not safe, with your calorie estimate. A good estimate is a much more powerful and useful tool than a poor estimate, even if the poor estimate is "safe".
  • meerkat70
    meerkat70 Posts: 4,605 Member
    Yes, I always take RMR out of the overall picture. I don't subtract it before logging, I just take it off my cals in my head, and leave some spare at the end of the day to take it into account.

    That said unless you're working with a very small deficit, it shouldn't really make a *huge* difference. One that should, theoretically, be compensated for with afterburn?
  • Kara_xxx
    Kara_xxx Posts: 635 Member
    It does make an important difference for low exertion long duration exercise. Let's say you take a leisurely three hour walk. Maybe you burn 690 calories. But net, you only burn 420 or so, depending on your size and all. So that's 270 phantom calories on your "safe to eat" list, provided the system calculated using gross. Again it's not a lot, but it is a six inch subway ham sandwich. You eat that and it's coming straight off your credit card so to speak.

    That's exactly it. We do a lot of long hikes and I never eat back more than 60% of those calories for exactly that reason.