If Body Fat % affects cals burned...cals burned calculator q

mollydubs

The standard plug ins for calories-burned calculators are sex, weight, height, and minutes spent. But we know body fat % affects how many calories you burn when you exercise (the leaner you are, the more you burn) so...is there any online calculator or formula that adds your body fat % to the equation? Or is it not quite so straight forward? Any fitness gurus wanna help a girl out?

I'm super lean (according to body fat % calculators) and I'm wondering just how far off - or not - these calorie burn calculators may be...But I have no interest in a HRM

Crazy4Healthy

That is a very interesting question and one I would like to hear the answer for. I was wondering the same thing since I'm realizing recently that my Body Media Fit has not changed much since I started wearing it and I know my body fat % has gone down and I have more muscle mass. Since muscle burns more, would be nice if it somehow factored that into my daily burn.

Can't wait to hear what people have to say.... nice post.

meshashesha2012

this one does
http://www.fat2fitradio.com/tools/bmr/

treetop57

this one does
http://www.fat2fitradio.com/tools/bmr/

It does for BMR, not for extra calories burned due to exercise. But for all I know, the only difference is to BMR, and the exercise calories are not a function of fat percentage. Good question, OP!

mollydubs

Hmm. Let me elaborate maybe.

Gym machines do not give accurate calories-burned read outs, as we've all sooner or later discovered. They know our weight (as long as we enter it) so we know it's not just weight alone that affects calories burned during exercise. And we know that people with lower body fat % burn more calories doing the same exercises as those with higher body fat %.

Sooooo, why no online calculators to take this into account? Is it just not that clear a science? (I'll admit, I have no grasp of science. In every single aspect of the term "science.")

glittersoul

http://www.myfitnesspal.com/topics/show/216471-does-body-fat-affect-calories-burned

Here is another thread to a similar question

katydid25

I saw this thread yesterday:
http://www.myfitnesspal.com/topics/show/548645-setup-polar-hrm-for-more-accurate-calorie-burn-for-known-bmr

It explains how to set the information in a heart rate monitor to get a more accurate number of calories burned when your body fat % is also taken into consideration. You basically figure the typical BMR of someone of your age, height and weight. Then do it a second time leaving out your age, but entering in your body fat percentage. Then a third time with age, height and weight, but you adjust the age until that BMR matchs the BMR you were given when you left of your age but included your body fat.

So maybe that would also be the age you'd enter on the machines you use instead of your actual age to get a better calorie readout?

treetop57

I saw this thread yesterday: http://www.myfitnesspal.com/topics/show/550679-if-body-fat-affects-cals-burned-cals-burned-calculator-q

That's a link to the thread we are on right now!

katydid25

I saw this thread yesterday: http://www.myfitnesspal.com/topics/show/550679-if-body-fat-affects-cals-burned-cals-burned-calculator-q

That's a link to the thread we are on right now!

Sorry about that! Thanks for pointing it out though It's corrected now!

treetop57

It explains how to set the information in a heart rate monitor to get a more accurate number of calories burned when your body fat % is also taken into consideration. You basically figure the typical BMR of someone of your age, height and weight. Then do it a second time leaving out your age, but entering in your body fat percentage. Then a third time with age, height and weight, but you adjust the age until that BMR matchs the BMR you were given when you left of your age but included your body fat.

So I went here (http://www.fat2fitradio.com/tools/bmr/) and tried that method.

With my actual information, it tells me that my "Harris-Benedict Formula" BMR is 2087. This is the one that uses age, but not body fat composition. With my actual information, my "Katch-McArdle Formula" BMR is 2108. This is the one that uses BF% but not age.

So I go back and reduce my age by three years and Harris-Benedict is 2107 and Katch-McArdle is still 2108. So if I'm understanding all this correct, I'm 51 but I have the body fat percentage typical of a 48 year-old. Woohoo!

Of course the other way to look at this is that even with my correct age, the two formulas differ by a grand total of 21 calories. Even I were very active, this is a difference of about 30 calories a day in estimated total daily energy expenditure.

(3500 calories/lb)/(30 calories/day) means this difference will result in an extra pound of fat loss every 117 days. Again I say, "Woohoo!"

I'm concluding that I'm too close to average for any of this to matter for me.

stayxtrue

You could always buy a HRM which takes into account your BF%

I know that mine has Weight, Sex, age, height, BF% this is going to give you the closest calories burned

katydid25

So if you find the age that gives you the same BMR as the equations that use body fat percentage instead of age, you are finding the age which has a body fat composition similar to yours. Give new meaning to "You've got the body of 25 year old"!

You make a good point! Unfortunately, thats not the case for me. It's more along the lines of, "Oh great... you have the metabolism of a 64 year old..." Someday, though. Someday.

Do the machines ask ones age? The exercise calculator on MFP does not, so this method definitely wouldn't work for that!

The machines do ask for your age. Unfortunately the only way I could think of use this method with the calculators on MFP would be change your age on your profile. (In which case, people might see my profile and acknowledge how great I look for a 64 year old??)

ninerbuff

There are so many variables to metabolism that you won't really get a truly accurate reading unless you have a Exercise metabolic test done. That would include a VO2 max test, an aerobic base test and an LT (lactate threshold) test.
Raising you RMR is the most important thing you can do though since about 75% of your fat calories are burned at rest.

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mollydubs

That post is all sorts of wacky. I wasn't far off on what I thought my bf% was, but apparently it means I have to go 8 years older to get the same bmr needs. Which seems...odd. Right? Do older people have naturally lesser bf%?

stayxtrue

There are so many variables to metabolism that you won't really get a truly accurate reading unless you have a Exercise metabolic test done. That would include a VO2 max test, an aerobic base test and an LT (lactate threshold) test.
Raising you RMR is the most important thing you can do though since about 75% of your fat calories are burned at rest.

A.C.E. Certified Personal & Group FitnessTrainer
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this i interesting and I seriously want to look into getting this done. However I have no idea who would be able to do this one for me

treetop57

That post is all sorts of wacky. I wasn't far off on what I thought my bf% was, but apparently it means I have to go 8 years older to get the same bmr needs. Which seems...odd. Right? Do older people have naturally lesser bf%?

The equations assume that older people have higher BF%.

mollydubs

That post is all sorts of wacky. I wasn't far off on what I thought my bf% was, but apparently it means I have to go 8 years older to get the same bmr needs. Which seems...odd. Right? Do older people have naturally lesser bf%?

The equations assume that older people have higher BF%.

That's what I would assume too. Which is why I find my results of that little test kinda puzzling. But as you pointed out with yours, it is only about a 30 calorie difference. I guess I'll survive!

treetop57

. . .

Raising you RMR is the most important thing you can do though since about 75% of your fat calories are burned at rest.

A.C.E. Certified Personal & Group FitnessTrainer
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I know that increasing lean muscle mass increases resting metabolic rate. What else does? I read an article that was way above my head that was advocating high intensity interval training (HIIT) because somehow it adds mitochondria (or increases the activity of mitochondria), so even the muscle I already have will burn more. Is that the sort of thing you recommend?

heybales

The standard plug ins for calories-burned calculators are sex, weight, height, and minutes spent. But we know body fat % affects how many calories you burn when you exercise (the leaner you are, the more you burn) so...is there any online calculator or formula that adds your body fat % to the equation? Or is it not quite so straight forward? Any fitness gurus wanna help a girl out?

I'm super lean (according to body fat % calculators) and I'm wondering just how far off - or not - these calorie burn calculators may be...But I have no interest in a HRM

Very true that BF%, or rather, the other side of the equation, LBM%, has an effect on what your metabolism really could be (I put it that way in case someone is suppressing it by not feeding at least that level).

And with faster metabolism because of more LBM, then more calories burned at all activities.

So as my thread on the Polar HRM setup for BMR suggests, Polar is doing a BMR calc with your stats and then uses that in a calorie burn calc.
But their BMR calc, like MFP Mifflin formula, or the ever popular Harris formula, does not take into account a more accurate BMR estimate using BF% - Katch McArdle.

So the studies that the BMR calcs come from are first off based on participants at healthy weight already. And second have avg LBM/BF percentage for healthy weight, I forget the ranges, but where you expect to see avg healthy ranges quoted.

So Mifflin and Harris BMR calc usually over-estimates BMR for obese people that have a higher percentage of fat than the study had. That means less LBM, that means really a smaller BMR.

That's one of the reasons it is said obese can go below their BMR safely without as many problems. True if just a little below, because their real BMR is indeed lower. Not true if they calc'd BMR by Katch method.

But the Katch BMR calc usually underestimates for obese, because fat does take energy to support by BMR, but only LBM is included in the formula.

So you couldn't really workout from machines what that might be. First they aren't even taking the bigger influence of calorie burn into consideration - HR.
You doing pace with HR at 160 will burn decently more calories than same pace at HR 130. And treadmill just doesn't know that.

You would have to find out what was the average bodyfat% of the folks that was used to create those tables/formulas for exercise calories. Because they only use weight, I've never seen age or gender. Some machines at least do that. Some of their manual may also suggest what avg HR they are expecting someone to do.

I really think your variance of error based on age, gender, and HR, is going to far over-shadow the difference in LBM between you and the control group.

heybales

With my actual information, it tells me that my "Harris-Benedict Formula" BMR is 2087. This is the one that uses age, but not body fat composition. With my actual information, my "Katch-McArdle Formula" BMR is 2108. This is the one that uses BF% but not age.

So I go back and reduce my age by three years and Harris-Benedict is 2107 and Katch-McArdle is still 2108. So if I'm understanding all this correct, I'm 51 but I have the body fat percentage typical of a 48 year-old. Woohoo!

Keep working out and that range will change even more!

Then you can have the body of an avg 30 yr old - woohoo! Actually, they use the BF% stat, but Katch calculates on LBM. So you have the LBM of your avg 48 yr old.

I try to think positive like that anyway. For instance, my measured max HR is the same as a 26 yr old according to the ever generic 220-age formula.

And for this method, not nearly as impressive, avg LBM of a 38.5 yr old. So 5 yrs younger. I'm just glad it's not my 5 yrs younger self, that would not be good. LOL.

How come my back feels like the back of a 55 yr old though!

heybales

That post is all sorts of wacky. I wasn't far off on what I thought my bf% was, but apparently it means I have to go 8 years older to get the same bmr needs. Which seems...odd. Right? Do older people have naturally lesser bf%?

It means you have the Lean Body Mass of an average lady your weight/height but 8 yrs older.

That's why I joked everyone would hope to get younger.

What it means is, at far as the Polar knows, you are being given an estimated calorie burn higher than you are really burning, because you have less LBM, therefore slower metabolism, then they are estimating you have.

But 8 yrs is nothing! Keep doing weight lifting, lose some more fat, and your LBM for weight/height will be right on, or even better! So younger.

ninerbuff

. . .

Raising you RMR is the most important thing you can do though since about 75% of your fat calories are burned at rest.

A.C.E. Certified Personal & Group FitnessTrainer
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I know that increasing lean muscle mass increases resting metabolic rate. What else does? I read an article that was way above my head that was advocating high intensity interval training (HIIT) because somehow it adds mitochondria (or increases the activity of mitochondria), so even the muscle I already have will burn more. Is that the sort of thing you recommend?

HIIT increases VO2 max. The more oxygen you use the higher the MET value. 8-10 MET is working hard and this hard work pays off by higher calorie burns and a small jump in RMR.

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Chipmaniac

And we know that people with lower body fat % burn more calories doing the same exercises as those with higher body fat %.

We do? I don't think this is the case. In fact, a person with a lower body fat % is likely to be fitter and more biomechanically sound and efficient. Thus, they are likely to burn less, not more.

I think you are confusing the additional BMR that lean muscle mass creates with the amount of energy it takes to do a specific exercise on a machine.

heybales

And we know that people with lower body fat % burn more calories doing the same exercises as those with higher body fat %.

We do? I don't think this is the case. In fact, a person with a lower body fat % is likely to be fitter and more biomechanically sound and efficient. Thus, they are likely to burn less, not more.

I think you are confusing the additional BMR that lean muscle mass creates with the amount of energy it takes to do a specific exercise on a machine.

Excellent point and better way to look at it.

Lady A at 200 lbs has LBM of 120 lbs, BF% of 40%.

Lady B at 140 lbs has LBM of 98 lbs, BF% of 30%.

Lady A is going to burn more calories, not only because of carrying more weight, but because higher LBM means higher metabolism too.

But then again, perhaps question was assuming same weighted person. In which case, smaller BF% automatically means higher LBM%, and that would mean higher calorie count.

Except as you point out, higher LBM probably means more muscle that can carry the load easier at equal pace, so lower HR to accomplish it, therefore less calories burned.

Ha! Basic premise is false. Nice work Mr Holmes!

ninerbuff

And we know that people with lower body fat % burn more calories doing the same exercises as those with higher body fat %.

We do? I don't think this is the case. In fact, a person with a lower body fat % is likely to be fitter and more biomechanically sound and efficient. Thus, they are likely to burn less, not more.

I think you are confusing the additional BMR that lean muscle mass creates with the amount of energy it takes to do a specific exercise on a machine.

Excellent point and better way to look at it.

Lady A at 200 lbs has LBM of 120 lbs, BF% of 40%.

Lady B at 140 lbs has LBM of 98 lbs, BF% of 30%.

Lady A is going to burn more calories, not only because of carrying more weight, but because higher LBM means higher metabolism too.

But then again, perhaps question was assuming same weighted person. In which case, smaller BF% automatically means higher LBM%, and that would mean higher calorie count.

Except as you point out, higher LBM probably means more muscle that can carry the load easier, so lower HR to accomplish it, therefore less calories burned.

Ha! Basic premise is false. Nice work Sherlock!

I think the only time that the higher LBM will burn more vs the higher body fat% is when both are the same weight and due to the fact that the one with higher LBM may be fitter doing the same exercises.

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Chipmaniac

And we know that people with lower body fat % burn more calories doing the same exercises as those with higher body fat %.

We do? I don't think this is the case. In fact, a person with a lower body fat % is likely to be fitter and more biomechanically sound and efficient. Thus, they are likely to burn less, not more.

I think you are confusing the additional BMR that lean muscle mass creates with the amount of energy it takes to do a specific exercise on a machine.

In which case, smaller BF% automatically means higher LBM%, and that would mean higher calorie count.

It's obvious a higher LBM would indeed burn more calories for every second of every day, however I'm not sure that a person with higher metabolism is going to expend extra energy to complete a specific task, with factors such as weight and fitness are normalized. In other words, their additional calorie burn will occur whether they exercise or not. Thus, the net calories burned in a given activity should be the same, all other things being equal.

Chipmaniac

And we know that people with lower body fat % burn more calories doing the same exercises as those with higher body fat %.

We do? I don't think this is the case. In fact, a person with a lower body fat % is likely to be fitter and more biomechanically sound and efficient. Thus, they are likely to burn less, not more.

I think you are confusing the additional BMR that lean muscle mass creates with the amount of energy it takes to do a specific exercise on a machine.

Excellent point and better way to look at it.

Lady A at 200 lbs has LBM of 120 lbs, BF% of 40%.

Lady B at 140 lbs has LBM of 98 lbs, BF% of 30%.

Lady A is going to burn more calories, not only because of carrying more weight, but because higher LBM means higher metabolism too.

But then again, perhaps question was assuming same weighted person. In which case, smaller BF% automatically means higher LBM%, and that would mean higher calorie count.

Except as you point out, higher LBM probably means more muscle that can carry the load easier, so lower HR to accomplish it, therefore less calories burned.

Ha! Basic premise is false. Nice work Sherlock!

I think the only time that the higher LBM will burn more vs the higher body fat% is when both are the same weight and due to the fact that the one with higher LBM may be fitter doing the same exercises.

I don't think it holds true that a fitter person will burn more during exercise than one who is not fit. In fact, I think the opposite is true. That's the basis of the higher heart rate = higher calorie burn theory that HRM's work off of. A fitter person will have a lower heart rate doing the exact same exercise and thus a lower actual burn, all other factors normalized.

mollydubs

That post is all sorts of wacky. I wasn't far off on what I thought my bf% was, but apparently it means I have to go 8 years older to get the same bmr needs. Which seems...odd. Right? Do older people have naturally lesser bf%?

It means you have the Lean Body Mass of an average lady your weight/height but 8 yrs older.

That's why I joked everyone would hope to get younger.

What it means is, at far as the Polar knows, you are being given an estimated calorie burn higher than you are really burning, because you have less LBM, therefore slower metabolism, then they are estimating you have.

But 8 yrs is nothing! Keep doing weight lifting, lose some more fat, and your LBM for weight/height will be right on, or even better! So younger.

But my point is...my body fat is at 16.6%...and I'm a woman. I have a super high LBM...

treetop57

That post is all sorts of wacky. I wasn't far off on what I thought my bf% was, but apparently it means I have to go 8 years older to get the same bmr needs. Which seems...odd. Right? Do older people have naturally lesser bf%?

I'm guessing I didn't explain the method clearly enough and you're coming up with a bogus number.

Using the formulas from this page ( http://www.cordianet.com/calculator.htm ) and algebra, I find this equation for the "effective age" of a woman, i.e. the age with the lean muscle mass assumed by the Harris-Benedict equations for a person of your weight and height. Height in inches, weight in pounds, and BF% as a number, not fraction (16.6, not 0.166 for you).

For women:

Age = (285 + 4.7 * height - 5.4476 * weight + 9.7976 * BF% * weight / 100) / 4.7

For men:

Age = (-304 + 12.7 * height - 3.5676 * weight + 9.7976 * BF% * weight / 100) / 6.8

Plug in your numbers, mollydubs, and see what you get. I think you are right that your "effective age" will be lower than your chronological age since 16.6% is very low for a woman. It wouldn't even surprise me if it turns out negative!

I hope this doesn't turn into another "order of operations" thread!

ninerbuff

And we know that people with lower body fat % burn more calories doing the same exercises as those with higher body fat %.

We do? I don't think this is the case. In fact, a person with a lower body fat % is likely to be fitter and more biomechanically sound and efficient. Thus, they are likely to burn less, not more.

I think you are confusing the additional BMR that lean muscle mass creates with the amount of energy it takes to do a specific exercise on a machine.

Excellent point and better way to look at it.

Lady A at 200 lbs has LBM of 120 lbs, BF% of 40%.

Lady B at 140 lbs has LBM of 98 lbs, BF% of 30%.

Lady A is going to burn more calories, not only because of carrying more weight, but because higher LBM means higher metabolism too.

But then again, perhaps question was assuming same weighted person. In which case, smaller BF% automatically means higher LBM%, and that would mean higher calorie count.

Except as you point out, higher LBM probably means more muscle that can carry the load easier, so lower HR to accomplish it, therefore less calories burned.

Ha! Basic premise is false. Nice work Sherlock!

I think the only time that the higher LBM will burn more vs the higher body fat% is when both are the same weight and due to the fact that the one with higher LBM may be fitter doing the same exercises.

I don't think it holds true that a fitter person will burn more during exercise than one who is not fit. In fact, I think the opposite is true. That's the basis of the higher heart rate = higher calorie burn theory that HRM's work off of. A fitter person will have a lower heart rate doing the exact same exercise and thus a lower actual burn, all other factors normalized.

In contrast what I meant to convey is that the fitter person will be able to do longer duration and higher intensity than that of their counter part, who isn't fit, thereby resulting in a higher calorie burn.

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