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Is every single body in the world intended to be within the so-called healthy BMI range?
Replies
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oy vey, still on this. always will be I suppose.
Somebody who puts deliberate effort into building mass is going to be outside of the BMI scale. That doesn't make them a true outlier though. They forced their body outside it. If they, as a person, were to stop putting great effort into building and maintaining mass, and lived a normal life the way normal people did, they would fall back into the normal BMI range quite quickly.
The only things that make somebody an outlier is if they naturally do not fit. For example, because of disease. If you have scoliosis that makes your measured height 2 inches shorter than it would be without a curved spine, you are an outlier.
Somebody who becomes statistically "obese" according to BMI because they workout or take drugs and put on 50 pounds of muscle is no more a statistical "outlier" than somebody who puts on 50 pounds of fat intentionally because they chose to eat 4000 calories a day for years.
That's not what an outlier is.
An outlier would be somebody has to put abnormal effort into MEETING the BMI standard. Which would be almost no one. Simply eating a healthy amount of food, engaging in a normal healthy amount of activity, and as a result having a normal, healthy body fat %, will, for 95%+ of people result in a BMI within the considerably wide health range.
I'm not sure "simply eating a healthy amount of food" and "simply engaging in a normal healthy amount of activity" are all that simple, especially for smaller women, older people, and people with jobs which require them to sit for hours every day. Older people have more aches, pains, disease conditions, and injuries, which can make it difficult to be active. Some people have jobs which mean they have to make a heroic effort to get in a reasonable amount of activity. And some small women maintain on a number of calories which would make me cry if that's all I was allowed to eat.
All of these people can maintain a normal BMI if they work at it, but it's not effortless, it requires vigilance and hard work.0 -
I got it. You are doubling down and saying that Arnold in his Mr. Olympia days was OBESE just as his BMI says he was. I say that means obese can not mean unhealthy as he was a specimen of humanity. With or without the use of hormones and as voted by the Mr. Olympia judges. So you prove my point of BMI not being correct in a non-outlier. Obese as a word has negative connotation. If we allow body builders to carry the diagnosis of obese then we have now redefined the word to simply mean heavy or big. I already know that I am heavy or big and no longer need the BMI to diagnose me as obese. Did I spell my point out slow enough? Having to much muscle is not unhealthy. Having worked your body into superhuman shape should not be a negative against you on someones clipboard either. Forget anything I said so far. Was Arnold obese as the BMI scale suggest? Was he unhealthy? Was he an outlier? Then he was simply bigger than some or heavy. That could be assessed by a 3 year old.9
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I got it. You are doubling down and saying that Arnold in his Mr. Olympia days was OBESE just as his BMI says he was. I say that means obese can not mean unhealthy as he was a specimen of humanity. With or without the use of hormones and as voted by the Mr. Olympia judges. So you prove my point of BMI not being correct in a non-outlier. Obese as a word has negative connotation. If we allow body builders to carry the diagnosis of obese then we have now redefined the word to simply mean heavy or big. I already know that I am heavy or big and no longer need the BMI to diagnose me as obese. Did I spell my point out slow enough? Having to much muscle is not unhealthy. Having worked your body into superhuman shape should not be a negative against you on someones clipboard either. Forget anything I said so far. Was Arnold obese as the BMI scale suggest? Was he unhealthy? Was he an outlier? Then he was simply bigger than some or heavy. That could be assessed by a 3 year old.
Steroid abuse isn't exactly healthy.9 -
rheddmobile wrote: »oy vey, still on this. always will be I suppose.
Somebody who puts deliberate effort into building mass is going to be outside of the BMI scale. That doesn't make them a true outlier though. They forced their body outside it. If they, as a person, were to stop putting great effort into building and maintaining mass, and lived a normal life the way normal people did, they would fall back into the normal BMI range quite quickly.
The only things that make somebody an outlier is if they naturally do not fit. For example, because of disease. If you have scoliosis that makes your measured height 2 inches shorter than it would be without a curved spine, you are an outlier.
Somebody who becomes statistically "obese" according to BMI because they workout or take drugs and put on 50 pounds of muscle is no more a statistical "outlier" than somebody who puts on 50 pounds of fat intentionally because they chose to eat 4000 calories a day for years.
That's not what an outlier is.
An outlier would be somebody has to put abnormal effort into MEETING the BMI standard. Which would be almost no one. Simply eating a healthy amount of food, engaging in a normal healthy amount of activity, and as a result having a normal, healthy body fat %, will, for 95%+ of people result in a BMI within the considerably wide health range.
I'm not sure "simply eating a healthy amount of food" and "simply engaging in a normal healthy amount of activity" are all that simple, especially for smaller women, older people, and people with jobs which require them to sit for hours every day. Older people have more aches, pains, disease conditions, and injuries, which can make it difficult to be active. Some people have jobs which mean they have to make a heroic effort to get in a reasonable amount of activity. And some small women maintain on a number of calories which would make me cry if that's all I was allowed to eat.
All of these people can maintain a normal BMI if they work at it, but it's not effortless, it requires vigilance and hard work.
sedentary life inside a cubical while eating excess amounts of junk food are behaviors outside the norm of human evolution.
but they are just that, behaviors. They're easy behaviors, but they're behaviors. People are not evolved to or genetically inclined toward sedentary life and a fast food diet.0 -
I think this is getting overly complicated.
BMI is a measure of the percentage of the population that is overweight or obese. It's a good proxy to use for that.
It's also a decent starting point to determine if an individual is overweight or obese, but of course the question is really if the person is overfat or obese (has excess body fat to an obese amount), and BMI is just a proxy for that. There are a number of outliers -- which just means someone who is overweight or obese by BMI but not by BF% measure -- and OF COURSE Schwartzenegger was an outlier, however he became one.
There's no test for "would be of a normal BMI weight when not overweight by bodyfat if you didn't work out as much" so you don't have to not fit in that category to be an outlier. The question is whether one who is above healthy BMI needs to lose weight to improve risks to be healthy or is an outlier.
I would agree that at a certain point BMI itself and not just body fat could be a problem, but it's not clear where that risk would begin, and we know excess fat is (on average) a problem.1 -
KenzieTeague wrote: »BMI is a horrible measurement of health. I wish they would get rid of that as the standard already. I would stick to actual measurments and fitness level as a more accurate assessment of where you are and where you should be.
BMI isn't a measure of health, or of how many fingers you have.4 -
usernameformyfitnesspal1 wrote: »John Cena 6 1 251 lbs BMI 32.3 OBESE...
John Cena = outlier who has gotten that way with lots of weight training a maybe some chemical help.3 -
. Wrong thread0
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Y’all seem pretty persistent In using the term “outlier” incorrectly.3
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I love MFP. My ribs hurt from laughing. Some think this BMI makes them better because they are not "fat" (or fat any more). Some are trying to pretend that we may not be as fat as our BMI says we are. Some are just here to argue for the sake of being right and because no one else will listen to them. I say it don't matter but if it don't matter to me I would quit coming back. This thing has its place but It honestly is a factor, along with heredity, drug use and abuse, diet, and sex life. That isn't factoring where you live, how you drive, and how you spend your evening hours. If nothing else kills me maybe I will get shinny enough soon enough that my fat don't kill me before something else does.6
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I tried to woo myself but it wouldn't let me. Lol1
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1. I never said she didn't have a large frame.
2. She contended bmi is not valid due to bone size which is invalid.
3. I never said she was over weight I said she might be on the top end because she had more weight than she wants to admit aka denial.
And I will not apologize for that.
I will stand by my original statement that those who say bmi doesn't apply to them are most likely in denial as the outliers are not that common.
People who are not educated in exercise science often use “bone size” as a substitute for “higher LBM”, since they are not familiar with other terminology. Fixating on their use of “bone size” because it is not precisely accurate confuses the issue
I can say with 100% certainty that the number of “outliers” from the BMI ranges is at least 20%. I can also say with 100% certainty that the actual number of people “in denial” about their weight is less than 10%.
Most of the people who have unrealistic expectations about their weight are those with “large frames” who think they can/should be able to reach the lower end of the BMI range for their height.
I feel I have a couple of points to clarify.
Sezxy: I did not say BMI is "not valid" (in total). I said it has QUALIFIED use. Which is to say it's not (as Aaron pointed out above) a tool that was designed or meant to be applied to judge any individual's health, but rather a good judge of populations, and a rough estimate for people who fall within a standard deviation of the mean for all body aspects (hip width, bone density, musculature, etc).
A detailed defense of my not being in denial is following in the spoiler.I hate to take this detour. I felt the point that I was not in denial was well-defended by others, I really don't understand why you had to throw it in. But since it's now been hammered on (though it isn't salient) let me put this here:- current height 5'8.25" - weight 155 lbs . BMI = 23.4
- tallest height 5'11" BMI = 21.6
- doctor-estimated real height 6'1" BMI = 20.4
Between the two of us, if our bone density falls at opposite ends of the normal range of most people, which seems likely, that difference alone accounted for nearly 8 lbs, your arbitrary "impossible" number. I imagine the rest of it is mostly lean body mass difference, though not all.. I do have a rather generous bosom even now, after all (34 DD to her 32 A). However, I am quite lean at this point. You can see shadows from my ribs front, back and side. I've got that hip bone ridge thing going on (wow does that hurt if I bump into something!), a flat stomach, and am starting to show muscle definition in my arms, calves, thighs, and abs. As a large-framed individual (by both current wrist and ankle measurements) that shouldn't be overly surprising.
It remains a valid observation that for an arbitrary weight cutoff uniform to all people of a given height that I will be far leaner than she would be at that given weight; and that means that health effects due to having too much adiposity would kick in for her at a much lower absolute weight than I. You can argue about the need to label her "overweight" at a lower weight, which may be and was the impetus for WHO recommendations to lower SOME Asian regions' cutoffs (interestingly they actually raised the cutoff for others!)
WHO, E. C. (2004). Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies. Lancet (London, England), 363(9403), 157.
The WHO has made available a PDF of the above citation for personal use only.
Now, if the WHO has taken the position that, for example, it is appropriate to label rural Thailanders "overweight" only above a BMI of 27, why is it such a contentious idea that there are other populations that demonstrate similarly higher risk-weight profiles?
Adzak, "bone size" is a real thing. People's bones vary in density. Weight is not the only thing that will create denser bones, any repeated, load-bearing stress (such as heavy work or weight lifting) will do the same thing. It doesn't generally account for everything, but I demonstrated that frame size (which refers to the overall breadth of skeletal structure) can account for considerable weight differences (just under 8 lbs) at the far ends of people considered to be within normal frame distribution. I specifically did not calculate the differences in other lean body mass aspects, such as organs or muscles, because the calculations would've required even more research, and because 8 lbs was the arbitrary weight differential that I was replying to.
p.s.
Holy Mother of Nested Quotes, Batman! I think I cut 8 or 9 layers out there to make this reply legible
I will be very blunt with you on this topic.
YOu used yourself and a friend to illustrate how bone size can impact BMI (which was not part of my original argument) without adding in that you personally are an Outlier due to a medical condition.
and if you had revealed that a lot of our discussion wouldn't have happened but of course your comparison wouldn't have held water either.....
My original premise was thisI always find those that dismiss BMI as a decent measure for the average person usually don't fall in the healthy range and either believe it's due to "bone" size etc or are in denial about their weight.
There are outliers in the world and they will fall outside the "health range" but not often and not for their entire life.
I used to think I would never fit in the healthy range due to "bone size'...psh...I was so in denial about being overweight/fat.
so for this part of the "debate" you and I will have to come to terms with a couple of things.
1. I said that there were outliers to start with
2. your argument was when I questioned if a certain # of pounds of a persons weight could be bone
3. you neglected to do a fair comparison because of 4
4. you neglected to reveal your were an outlier
and so what this has become is non sense and I am not going to respond further to this subdebate of this particular thread. If you choose to that is fine but I won't be.
Except the friend is not my CURRENT height. She is my PAST height. I see no point in making a comparison based on the height caused by my condition. And the mass of bones difference remains valid. If both of us exist in the normal range of bone density and frame frame size, with the same overall height, then nearly 8 lbs of difference between us can be directly attributed to the skeletal structure alone. This has nothing to do with my medical condition or being an "outlier".
I'm replying because I don't want people to be left with the bad argument you're giving being uncontested.
I gather you and your friend have the same height now, but your height has shrunk 5 inches due to disease.
I don't think @SezxyStef was saying you should compare yourself to your friend based on your current height.0 -
I gather you and your friend have the same height now, but your height has shrunk 5 inches due to disease.
I don't think @SezxyStef was saying you should compare yourself to your friend based on your current height.
No. In 1992, when we met, my friend and I were both 5'11". I use this as my reference height for my health because it was my tallest attained height. I would never compare my bmi at my current height with that of another woman who is also 5'8.25" because it would have no meaning.
People are getting all hung up on my use of two real people to illustrate that bone weight alone can account for 8 lbs between individuals of like height. But that math is applicable to any two individuals ; it just so happens that at 5'11" the accepted endpoints of normal and regular variation in bone mass come almost perfectly to 8 lbs.3 -
BMI seems to be more accurate (on average) for women. I think it is absurd that men and women have the same BMI scale since our bodies store fat completely differently. I've noticed for men it seems highly inaccurate. It still is a good ballpark estimate. My dad is very very thin, but super tall. He is overweight, but anyone looking at him would think he is quite a thin guy. BMI scale is terrible for tall people and men.0
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I gather you and your friend have the same height now, but your height has shrunk 5 inches due to disease.
I don't think @SezxyStef was saying you should compare yourself to your friend based on your current height.
No. In 1992, when we met, my friend and I were both 5'11". I use this as my reference height for my health because it was my tallest attained height. I would never compare my bmi at my current height with that of another woman who is also 5'8.25" because it would have no meaning.
People are getting all hung up on my use of two real people to illustrate that bone weight alone can account for 8 lbs between individuals of like height. But that math is applicable to any two individuals ; it just so happens that at 5'11" the accepted endpoints of normal and regular variation in bone mass come almost perfectly to 8 lbs.
here is your original post
"So I'm 5'9" and currently weigh 155 lbs. I have a good friend who is 5'9" and weighs 130 lbs. If you put her wrist and mine overlapping, mine is a good 33% larger. She has ankles that measure around half what mine do. She has beautiful, delicate hands and graceful collarbones. Even thin, my bones look massive. Honestly, the only shocking thing is that I ONLY weigh 25 lbs more than her given the clear difference in our frames."
so you were saying again you used your original height???? please show bring forth that post.
and when you illustrated that bone could account for 8lbs you used 12% of weight for your friend and 15% for you...so again apples and oranges are both fruit but comparing them as the same is invalid.3 -
Here's a good article supporting the idea that BMI is generally a good measure: https://examine.com/nutrition/how-valid-is-bmi-as-a-measure-of-health-and-obesity/
Summation:
"If you are normal weight or overweight according to BMI (18.5-29.9) there is still a chance you are actually obese, and thus is primarily due to low levels of lean mass (muscle, water, and glycogen).
If you are obese according to BMI, you are most likely obese according to body fat percentage as well. When sampling from the general population, over 95% of men and 99% of women identified as obese by BMI were obese via body fat levels. [My note, but there are other studies showing otherwise, these seem to be all over the place and likely depend on the population examined.]
Outliers to this dataset, those who have enough lean mass to be classified as obese by BMI but not by body fat percentage, are far and few in society. These persons would normally be highly active athletes or dedicated 'weekend warriors', and it is unlikely sedentary persons or those with infrequent exercise habits would be these outliers."2 -
I will add that one of the problems in comparing the various studies and why they generally tend to focus on the "obese" measure is that there doesn't seem to be a clear BF cutoff beyond what = obese. There's no a lower one that is agreed on that = overweight but not obese, and therefore some of the studies assume not obese = healthy and compare obese by BF% (generally over 25% for men, over 35% for women, which are quite high, IMO) to overweight or obese and find more people identified as above a healthy BMI who are not obese. This is what is discussed here: https://www.nytimes.com/interactive/projects/cp/summer-of-science-2015/latest/how-often-is-bmi-misleading. Thus, it comes to a different conclusion than the study Examine is focusing on.
Other studies, like the one I cited upthread, try to create a middle category for overweight but not obese by body fat, which seems to be a better approach. I am not sure what the studies of health and BF% say is an increased risk, that would be very interesting. The studies of BMI and increased risk don't cull out the outliers (people who are over a healthy BMI but don't have excess body fat or the likely larger group of people with a healthy BMI and excess body fat) so that would be interesting too, to compare all these groups. The "fat but fit?" study showed that people with metabolic syndrome but healthy BMI had more risk (on average) than people without metabolic syndrome but overweight or obese BMI, and part of that may well be that the first group contains a lot of people with excess body fat regardless of BMI and the second contains some without excess body fat.0 -
I gather you and your friend have the same height now, but your height has shrunk 5 inches due to disease.
I don't think @SezxyStef was saying you should compare yourself to your friend based on your current height.
No. In 1992, when we met, my friend and I were both 5'11". I use this as my reference height for my health because it was my tallest attained height. I would never compare my bmi at my current height with that of another woman who is also 5'8.25" because it would have no meaning.
People are getting all hung up on my use of two real people to illustrate that bone weight alone can account for 8 lbs between individuals of like height. But that math is applicable to any two individuals ; it just so happens that at 5'11" the accepted endpoints of normal and regular variation in bone mass come almost perfectly to 8 lbs.
here is your original post
"So I'm 5'9" and currently weigh 155 lbs. I have a good friend who is 5'9" and weighs 130 lbs. If you put her wrist and mine overlapping, mine is a good 33% larger. She has ankles that measure around half what mine do. She has beautiful, delicate hands and graceful collarbones. Even thin, my bones look massive. Honestly, the only shocking thing is that I ONLY weigh 25 lbs more than her given the clear difference in our frames."
so you were saying again you used your original height???? please show bring forth that post.
and when you illustrated that bone could account for 8lbs you used 12% of weight for your friend and 15% for you...so again apples and oranges are both fruit but comparing them as the same is invalid.
You're right. I should've used 5'11" not 5'9" (height I spent about 10 years at).
But 15% of 155 is still 23.25 and 12% of 130 is still 15.6. Those weights are both in the healthy range at either, and the difference is still almost 8 lbs.1 -
I gather you and your friend have the same height now, but your height has shrunk 5 inches due to disease.
I don't think @SezxyStef was saying you should compare yourself to your friend based on your current height.
No. In 1992, when we met, my friend and I were both 5'11". I use this as my reference height for my health because it was my tallest attained height. I would never compare my bmi at my current height with that of another woman who is also 5'8.25" because it would have no meaning.
People are getting all hung up on my use of two real people to illustrate that bone weight alone can account for 8 lbs between individuals of like height. But that math is applicable to any two individuals ; it just so happens that at 5'11" the accepted endpoints of normal and regular variation in bone mass come almost perfectly to 8 lbs.
YOU are literally an outlier. Something outside of your behavior is causing you to not fit the BMI model as intended.0 -
I gather you and your friend have the same height now, but your height has shrunk 5 inches due to disease.
I don't think @SezxyStef was saying you should compare yourself to your friend based on your current height.
No. In 1992, when we met, my friend and I were both 5'11". I use this as my reference height for my health because it was my tallest attained height. I would never compare my bmi at my current height with that of another woman who is also 5'8.25" because it would have no meaning.
People are getting all hung up on my use of two real people to illustrate that bone weight alone can account for 8 lbs between individuals of like height. But that math is applicable to any two individuals ; it just so happens that at 5'11" the accepted endpoints of normal and regular variation in bone mass come almost perfectly to 8 lbs.
here is your original post
"So I'm 5'9" and currently weigh 155 lbs. I have a good friend who is 5'9" and weighs 130 lbs. If you put her wrist and mine overlapping, mine is a good 33% larger. She has ankles that measure around half what mine do. She has beautiful, delicate hands and graceful collarbones. Even thin, my bones look massive. Honestly, the only shocking thing is that I ONLY weigh 25 lbs more than her given the clear difference in our frames."
so you were saying again you used your original height???? please show bring forth that post.
and when you illustrated that bone could account for 8lbs you used 12% of weight for your friend and 15% for you...so again apples and oranges are both fruit but comparing them as the same is invalid.
You're right. I should've used 5'11" not 5'9" (height I spent about 10 years at).
But 15% of 155 is still 23.25 and 12% of 130 is still 15.6. Those weights are both in the healthy range at either, and the difference is still almost 8 lbs.
yes 15% of 155 is 23.25 but 15% of 130 is 19.5...4lbs...apples to apples.
Is it possible for one to be 15% and one to be 12% sure...and have an 8lb difference sure but it probably is not the norm just like having an overweight BMI and actually not being overweight is not the norm...
but again...smh.
so please explain how your friend lost 5 inches as well? and can be so delicate if they were 5 ft 11 20 years ago??? Unless you are now contending that your friend is 5 ft 11 and 130lbs...which puts your friend at 18.1 BMI.
"No. In 1992, when we met, my friend and I were both 5'11". I use this as my reference height for my health because it was my tallest attained height. I would never compare my bmi at my current height with that of another woman who is also 5'8.25" because it would have no meaning. "
"So I'm 5'9" and currently weigh 155 lbs. I have a good friend who is 5'9" and weighs 130 lbs. If you put her wrist and mine overlapping, mine is a good 33% larger.[/b] She has ankles that measure around half what mine do. She has beautiful, delicate hands and graceful collarbones. Even thin, my bones look massive. Honestly, the only shocking thing is that I ONLY weigh 25 lbs more than her given the clear difference in our frames."
I will admit I am blond and it's friday and I might be a little slow but...the two posts above that you made seem to be in complete contradiction to each other????
Awaiting clarification.
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I love MFP. My ribs hurt from laughing. Some think this BMI makes them better because they are not "fat" (or fat any more). Some are trying to pretend that we may not be as fat as our BMI says we are. Some are just here to argue for the sake of being right and because no one else will listen to them. I say it don't matter but if it don't matter to me I would quit coming back. This thing has its place but It honestly is a factor, along with heredity, drug use and abuse, diet, and sex life. That isn't factoring where you live, how you drive, and how you spend your evening hours. If nothing else kills me maybe I will get shinny enough soon enough that my fat don't kill me before something else does.
Being right is actually pretty important. Being right is what allows you to take informed action rather than misinformed action when it comes to making decisions. People "arguing for the sake of being right" in a debate thread seems like a pretty logical thing to do to me. What other reason would people have to post on a debate thread other than to argue what they feel is right? You seem to be having some sort of emotional reaction to BMI that you wish to be acknowledged. Okay, I understand that BMI pisses you off because people misuse it and think it means something it doesn't. I guess it makes you feel good to point it out and you feel like other people explaining what BMI is actually used for detracts from that in some way. I'm sorry if discussing what BMI can and cannot be used for is a buzzkill for you, I'm not sure what to say about that though.10 -
If the world went by BMI
Arnold Schwarzenegger in his prime would be considered super morbidly obese as would Dwayne 'the rock' Johnson, it's a dated measurement of health.15 -
Lets pretend there is a rule that is quick to implement and fits 95% of use cases. You have two options.
Option 1: acknowledge that such a rule has uses
Option 2: Point out the 5% of the time that the rule does not yield the correct answer and mock said rule as being useless.
So what do you think. Do you think such a rule has no functional use? That being correct 95% of the time for very little effort of input has no value? Let me put it in another way then....
On a case by case basis if you are dealing with one piece of data (an individual) then maybe you would choose to implement the rule that works 99.9% of the time instead but takes much more effort and time to implement. That would be rational, I think that would probably be the right call. If, however, you are dealing with a massive dataset it would probably make a lot more sense to use the rule that is right 95% of the time but takes a fraction of the time to implement.
BMI is like the 95% rule. It is used for analysis of populations (large datasets). If applied to an individual by an individual there are certainly better methods one could choose than BMI. That doesn't make BMI "wrong" or "useless".
I mean, people get that right? That isn't a hard concept to understand is it?7 -
Viking_Batman wrote: »If the world went by BMI
Arnold Schwarzenegger in his prime would be considered super morbidly obese as would Dwayne 'the rock' Johnson, it's a dated measurement of health.
It's not a measure of health. If the world used BMI to decide how many fingers people have, jewelry stores would sell a lot of rings.3 -
Viking_Batman wrote: »If the world went by BMI
Arnold Schwarzenegger in his prime would be considered super morbidly obese as would Dwayne 'the rock' Johnson, it's a dated measurement of health.
Arnold and The Rock are not outliers and do not disprove the rule. They have worked hard to engage in behavior that would yield a high BMI and low BF%, intentionally.
People need to stop using them as examples of "outliers."
tomteboda is an outlier, a true outlier0 -
Viking_Batman wrote: »If the world went by BMI
Arnold Schwarzenegger in his prime would be considered super morbidly obese as would Dwayne 'the rock' Johnson, it's a dated measurement of health.
That...is not...what BMI...is for. If you use a hammer to try to cut down a tree yeah you might think the hammer is a useless tool but maybe, just maybe, you just aren't using the hammer for its intended purpose. Maybe there is nothing wrong with a hammer as a tool.
BMI isn't for individuals, it is for populations. It is a statistical measure. If you attempt to use a tool for the wrong thing of course it doesn't work very well.11 -
Viking_Batman wrote: »If the world went by BMI
Arnold Schwarzenegger in his prime would be considered super morbidly obese as would Dwayne 'the rock' Johnson, it's a dated measurement of health.
Does not fit everyone does not mean "dated."
No one claims it fits everyone (or at least very few (if any, I'm not sure) people of those involved in the current discussion). Nor is the proper use of BMI to trump/outweigh other better measures.0 -
Aaron_K123 wrote: »Lets pretend there is a rule that is quick to implement and fits 95% of use cases. You have two options.
Option 1: acknowledge that such a rule has uses
Option 2: Point out the 5% of the time that the rule does not yield the correct answer and mock said rule as being useless.
So what do you think. Do you think such a rule has no functional use? That being correct 95% of the time for very little effort of input has no value? Let me put it in another way then....
On a case by case basis if you are dealing with one piece of data (an individual) then maybe you would choose to implement the rule that works 99.9% of the time instead but takes much more effort and time to implement. That would be rational, I think that would probably be the right call. If, however, you are dealing with a massive dataset it would probably make a lot more sense to use the rule that is right 95% of the time but takes a fraction of the time to implement.
BMI is like the 95% rule. It is used for analysis of populations (large datasets). If applied to an individual by an individual there are certainly better methods one could choose than BMI. That doesn't make BMI "wrong" or "useless".
I mean, people get that right? That isn't a hard concept to understand is it?
You wouldn't think so.0 -
Aaron_K123 wrote: »Viking_Batman wrote: »If the world went by BMI
Arnold Schwarzenegger in his prime would be considered super morbidly obese as would Dwayne 'the rock' Johnson, it's a dated measurement of health.
That...is not...what BMI...is for. If you use a hammer to try to cut down a tree yeah you might think the hammer is a useless tool but maybe, just maybe, you just aren't using the hammer for its intended purpose. Maybe there is nothing wrong with a hammer as a tool.
BMI isn't for individuals, it is for populations. It is a statistical measure. If you attempt to use a tool for the wrong thing of course it doesn't work very well.
ok, let's be a little clear on something.
As a tool it predicts that 95% of people in a population would be approximately within the normal BMI range under normal conditions, with no extenuating factors. Not that any particular percentage of people WILL be in that range.
Likewise, on an individual level, it predicts that there is a 95% probability that any particular individual in a population would be in the normal BMI range baring external conditions or other factors.
Your average person would have a normal BMI if they didn't lead a sedentary lifestyle and each more calories than their body needs.
Likewise, your average person would have a normal BMI if they didn't spend hours a day in the gym cultivating extra-ordinary muscle mass.
If you, as an individual, do not have a "normal" BMI, then the next step is to take additional factors into consideration. If they are negative, not enough exercise and too much food, then they should be eliminated for the good of your health. If they are positive, lots of exercise and proper nutrition, then they should be encouraged. If they are outside of your control, disease or disorder, then they should be treated. But BMI provides a reasonable baseline estimate from which to start, and to identify if there are mitigating factors that need to be addressed (for good or bad.)4 -
Aaron_K123 wrote: »Viking_Batman wrote: »If the world went by BMI
Arnold Schwarzenegger in his prime would be considered super morbidly obese as would Dwayne 'the rock' Johnson, it's a dated measurement of health.
That...is not...what BMI...is for. If you use a hammer to try to cut down a tree yeah you might think the hammer is a useless tool but maybe, just maybe, you just aren't using the hammer for its intended purpose. Maybe there is nothing wrong with a hammer as a tool.
BMI isn't for individuals, it is for populations. It is a statistical measure. If you attempt to use a tool for the wrong thing of course it doesn't work very well.
ok, let's be a little clear on something.
As a tool it predicts that 95% of people in a population would be approximately within the normal BMI range under normal conditions, with no extenuating factors. Not that any particular percentage of people WILL be in that range.
Likewise, on an individual level, it predicts that there is a 95% probability that any particular individual in a population would be in the normal BMI range baring external conditions or other factors.
Your average person would have a normal BMI if they didn't lead a sedentary lifestyle and each more calories than their body needs.
Likewise, your average person would have a normal BMI if they didn't spend hours a day in the gym cultivating extra-ordinary muscle mass.
If you, as an individual, do not have a "normal" BMI, then the next step is to take additional factors into consideration. If they are negative, not enough exercise and too much food, then they should be eliminated for the good of your health. If they are positive, lots of exercise and proper nutrition, then they should be encouraged. If they are outside of your control, disease or disorder, then they should be treated. But BMI provides a reasonable baseline estimate from which to start, and to identify if there are mitigating factors that need to be addressed (for good or bad.)
I was taking into account the idea of applying BMI as a metric of health (yes I understand that is not exactly what it is for but that is how people are using it). What I was saying was that for a given population 95% of the time if you apply BMI as a means to determine if someone is obese or not the answer you get will be right (BMI is 28, person is predicted to be obese...person is obese) while 5% it will be wrong (BMI is 28, person is predicted to be obese...person is not obese). One could argue that that is just a misapplication of BMI in the first place but I'm trying to speak to the context of its use within this debate.
So as a "rule for determining whether a person is obese" maybe it has a 95% accuracy (I made up that number, just giving it as an example). Maybe a DEXA scan has a 99.9% accuracy. If you are dealing with an individual and have both options then yeah go with the DEXA. If you are dealing with a large population and want to know what percentage is obese you aren't going to DEXA scan the entire populace so go with BMI.
BMI is not a normalized distribution. What is considered a "normal BMI" is not the peak of a bell curve or something it is based on studies of BMI compared to measures of body compisition. You could have a population where the majority of people do not have a "normal" BMI.5
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