Unfair Rant Time
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No, tall people are at an advantage there.DeguelloTex wrote: »I think it's unfair that BMI penalizes tall people.
I think it's unfair that I read that as penis
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DeguelloTex wrote: »
Because of the square root in the denominator of the formula. People scale in three dimensions, not two. The constants in the numerator and the too-low scaling factor in the denominator mean the results are off by about a point for each six inches by which you differ from the average adult height. The formula outputs a value that's that much too high on the tall end of the curve and that much too low on the short end of the curve. Someone, ahem, 15 inches taller than average gets a BMI about 2.5 points higher than it should be if the scaling in the formula more closely matched the scaling in the physical world.DeguelloTex wrote: »
No, it plays in favor of short people, generally.samhennings wrote: »DeguelloTex wrote: »
It does, because it only rises as the square of the height but people's mass rises as more than the square but less than the cube. The farther you are from the mean, the more BMI understates what your mass should be if you're tall and overstates it if you're short.DeguelloTex wrote: »I think it's unfair that BMI penalizes tall people.
It doesn't. That's why height is part of the equation.
Was just gonig to say - it plays against short people as well. Im 5"6', 12 stone and in perfectly good shape - because Im quite broad/stocky built. According to BMI I should be somewhere around 2 stone lighter. If I ever got that low people would assume I was critically ill!
How so?
You've explained patiently, but I still don't get it. If you're very tall, the number in the denominator is squared (even larger), so weight in kg divided by height (meters) squared is an even smaller number. Are you saying its a disadvantage that BMI outputs a(n artificially) smaller number for tall men?
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The height should be more than squared, rather than squared, which would make the denominator even larger, which would make the output of the calculation smaller.DeguelloTex wrote: »
Because of the square root in the denominator of the formula. People scale in three dimensions, not two. The constants in the numerator and the too-low scaling factor in the denominator mean the results are off by about a point for each six inches by which you differ from the average adult height. The formula outputs a value that's that much too high on the tall end of the curve and that much too low on the short end of the curve. Someone, ahem, 15 inches taller than average gets a BMI about 2.5 points higher than it should be if the scaling in the formula more closely matched the scaling in the physical world.DeguelloTex wrote: »
No, it plays in favor of short people, generally.samhennings wrote: »DeguelloTex wrote: »
It does, because it only rises as the square of the height but people's mass rises as more than the square but less than the cube. The farther you are from the mean, the more BMI understates what your mass should be if you're tall and overstates it if you're short.DeguelloTex wrote: »I think it's unfair that BMI penalizes tall people.
It doesn't. That's why height is part of the equation.
Was just gonig to say - it plays against short people as well. Im 5"6', 12 stone and in perfectly good shape - because Im quite broad/stocky built. According to BMI I should be somewhere around 2 stone lighter. If I ever got that low people would assume I was critically ill!
How so?
You've explained patiently, but I still don't get it. If you're very tall, the number in the denominator is squared (even larger), so weight in kg divided by height (meters) squared is an even smaller number. Are you saying its a disadvantage that BMI outputs a(n artificially) smaller number for tall men?
The larger the number (height) the faster it scales when raised to a positive power. 81 inches scales faster when raised to the 2.5 power rather than squared than 66 scales from being raised from a square to the 2.5 power.
Maybe think of it along these lines: imagine the current BMI outputs a value like 1/4. If it output 1/5 -- larger denominator -- the value of the output would be lower. Just like 20% is lower than 25%. Right now, it puts out something like 1/4, because the height parameter doesn't scale high enough.
Since the formula is normalized toward the average person, this makes the output for short people correspondingly lower than it should be.
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DeguelloTex wrote: »
The height should be more than squared, rather than squared, which would make the denominator even larger, which would make the output of the calculation smaller.DeguelloTex wrote: »
Because of the square root in the denominator of the formula. People scale in three dimensions, not two. The constants in the numerator and the too-low scaling factor in the denominator mean the results are off by about a point for each six inches by which you differ from the average adult height. The formula outputs a value that's that much too high on the tall end of the curve and that much too low on the short end of the curve. Someone, ahem, 15 inches taller than average gets a BMI about 2.5 points higher than it should be if the scaling in the formula more closely matched the scaling in the physical world.DeguelloTex wrote: »
No, it plays in favor of short people, generally.samhennings wrote: »DeguelloTex wrote: »
It does, because it only rises as the square of the height but people's mass rises as more than the square but less than the cube. The farther you are from the mean, the more BMI understates what your mass should be if you're tall and overstates it if you're short.DeguelloTex wrote: »I think it's unfair that BMI penalizes tall people.
It doesn't. That's why height is part of the equation.
Was just gonig to say - it plays against short people as well. Im 5"6', 12 stone and in perfectly good shape - because Im quite broad/stocky built. According to BMI I should be somewhere around 2 stone lighter. If I ever got that low people would assume I was critically ill!
How so?
You've explained patiently, but I still don't get it. If you're very tall, the number in the denominator is squared (even larger), so weight in kg divided by height (meters) squared is an even smaller number. Are you saying its a disadvantage that BMI outputs a(n artificially) smaller number for tall men?
Maybe think of it along these lines: imagine the current BMI outputs a value like 1/4. If it output 1/5 -- larger denominator -- the value of the output would be lower. Just like 20% is lower than 25%. Right now, it puts out something like 1/4, because the height parameter doesn't scale high enough.
Since the formula is normalized toward the average person, this makes the output for short people correspondingly lower than it should be.
Do you have any reading material about the formula being normalized towards the average/shorter person?
The way I see it, if you and a 5'9" person weigh the same, you have a much lower BMI. The 1/4 vs. 1/5 scenario is already occurring because you're taller
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I think it's unfair that some people wanna be taller ( like me) and some don't like being so tall and we can't swap0
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Unfair is in the eye of the beholder..but sometimes I remind myself I'm pretty damn lucky because I have drinkable, temp changing water that pours from my wall at will. Perspective achieved!0
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Here's something from a mathematician at Oxford. His explanation might make more sense to you.DeguelloTex wrote: »
The height should be more than squared, rather than squared, which would make the denominator even larger, which would make the output of the calculation smaller.DeguelloTex wrote: »
Because of the square root in the denominator of the formula. People scale in three dimensions, not two. The constants in the numerator and the too-low scaling factor in the denominator mean the results are off by about a point for each six inches by which you differ from the average adult height. The formula outputs a value that's that much too high on the tall end of the curve and that much too low on the short end of the curve. Someone, ahem, 15 inches taller than average gets a BMI about 2.5 points higher than it should be if the scaling in the formula more closely matched the scaling in the physical world.DeguelloTex wrote: »
No, it plays in favor of short people, generally.samhennings wrote: »DeguelloTex wrote: »
It does, because it only rises as the square of the height but people's mass rises as more than the square but less than the cube. The farther you are from the mean, the more BMI understates what your mass should be if you're tall and overstates it if you're short.DeguelloTex wrote: »I think it's unfair that BMI penalizes tall people.
It doesn't. That's why height is part of the equation.
Was just gonig to say - it plays against short people as well. Im 5"6', 12 stone and in perfectly good shape - because Im quite broad/stocky built. According to BMI I should be somewhere around 2 stone lighter. If I ever got that low people would assume I was critically ill!
How so?
You've explained patiently, but I still don't get it. If you're very tall, the number in the denominator is squared (even larger), so weight in kg divided by height (meters) squared is an even smaller number. Are you saying its a disadvantage that BMI outputs a(n artificially) smaller number for tall men?
Maybe think of it along these lines: imagine the current BMI outputs a value like 1/4. If it output 1/5 -- larger denominator -- the value of the output would be lower. Just like 20% is lower than 25%. Right now, it puts out something like 1/4, because the height parameter doesn't scale high enough.
Since the formula is normalized toward the average person, this makes the output for short people correspondingly lower than it should be.
Do you have any reading material about the formula being normalized towards the average/shorter person?
The way I see it, if you and a 5'9" person weigh the same, you have a much lower BMI. The 1/4 vs. 1/5 scenario is already occurring because you're taller
https://people.maths.ox.ac.uk/trefethen/bmi.html0 -
the only unfair thing i see is that i cant eat whatever i want, whenever i want, in whatever quantity i want... and still lose weight!
HOW RUDE!0 -
It's unfair that Blizzards from Dairy Queen have calories...0
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It's ironic that when I went looking for an unfair meme I found one with Tom Brady:
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ogmomma2012 wrote: »It's unfair that Blizzards from Dairy Queen have calories...
^ I agree^0 -
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FoodFitnessTravel wrote: »try gaining weight as a skinny guy.
That complaint can get you in trouble around here although I do understand. My carnivorous beanpole is home for the summer and demanding beef, hot dogs, or pizza for supper every night. Not to mention his weekend breakfasts of a pound of bacon and a half dozen homemade biscuits. No kidding, he has been wearing the same waist size since eighth grade.0 -
DeguelloTex wrote: »
Because of the square root in the denominator of the formula. People scale in three dimensions, not two. The constants in the numerator and the too-low scaling factor in the denominator mean the results are off by about a point for each six inches by which you differ from the average adult height. The formula outputs a value that's that much too high on the tall end of the curve and that much too low on the short end of the curve. Someone, ahem, 15 inches taller than average gets a BMI about 2.5 points higher than it should be if the scaling in the formula more closely matched the scaling in the physical world.DeguelloTex wrote: »
No, it plays in favor of short people, generally.samhennings wrote: »DeguelloTex wrote: »
It does, because it only rises as the square of the height but people's mass rises as more than the square but less than the cube. The farther you are from the mean, the more BMI understates what your mass should be if you're tall and overstates it if you're short.DeguelloTex wrote: »I think it's unfair that BMI penalizes tall people.
It doesn't. That's why height is part of the equation.
Was just gonig to say - it plays against short people as well. Im 5"6', 12 stone and in perfectly good shape - because Im quite broad/stocky built. According to BMI I should be somewhere around 2 stone lighter. If I ever got that low people would assume I was critically ill!
How so?
I don't think that's an advantage at all. I'm 4'11 and of Asian descent, so I'm genetically predisposed to a higher body fat %. The # that is recommended for me by the BMI chart is likely far too high. And yet if I were to be open about a goal that is technically "underweight" by BMI standards, that wouldn't garner a lot of support.
Just because the number is technically within normal, that doesn't make me any healthier.
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pollypocket1021 wrote: »DeguelloTex wrote: »
Because of the square root in the denominator of the formula. People scale in three dimensions, not two. The constants in the numerator and the too-low scaling factor in the denominator mean the results are off by about a point for each six inches by which you differ from the average adult height. The formula outputs a value that's that much too high on the tall end of the curve and that much too low on the short end of the curve. Someone, ahem, 15 inches taller than average gets a BMI about 2.5 points higher than it should be if the scaling in the formula more closely matched the scaling in the physical world.DeguelloTex wrote: »
No, it plays in favor of short people, generally.samhennings wrote: »DeguelloTex wrote: »
It does, because it only rises as the square of the height but people's mass rises as more than the square but less than the cube. The farther you are from the mean, the more BMI understates what your mass should be if you're tall and overstates it if you're short.DeguelloTex wrote: »I think it's unfair that BMI penalizes tall people.
It doesn't. That's why height is part of the equation.
Was just gonig to say - it plays against short people as well. Im 5"6', 12 stone and in perfectly good shape - because Im quite broad/stocky built. According to BMI I should be somewhere around 2 stone lighter. If I ever got that low people would assume I was critically ill!
How so?
I don't think that's an advantage at all. I'm 4'11 and of Asian descent, so I'm genetically predisposed to a higher body fat %. The # that is recommended for me by the BMI chart is likely far too high. And yet if I were to be open about a goal that is technically "underweight" by BMI standards, that wouldn't garner a lot of support.
Just because the number is technically within normal, that doesn't make me any healthier.
Yeah that's not true though is it?
I know there's a BMI chart specifically for Asian (and yes BMI is a population measure) in terms of the range within which health issues are minimised
My understanding is that the lower end of the scale is the same as for Caucasians, it's merely the upper limit that is lower
If you want to drop into underweight with the associated increased risks then I'd recommend doing so under the direct supervision of a doctor
Of course general caveats re BMI on an individual basis apply0
This discussion has been closed.
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