BMI - A poor measure of weight and obesity

[Pilotman]

I am a fit and slim older male, carrying a very small percentage of body fat.  According to that idiotic measure, the BMI, I am overweight, by 2lbs. It's such a crude measure of weight that I am surprised that anyone takes any notice of it at all.  It destroys the morale of those who are trying to get to a healthy weight, by placed an unrealistic expectation and target for weight loss that takes no account of body shape, lifestyle and fitness.  It's about time the medical profession ditched it.   

[metempsychotic]

2 lbs is a single kilo, I do not see the issue. 

 

BMI is a simplistic mathematic formula and makes no claims to be otherwise. 

[Pilotman]

2 minutes ago, metempsychotic said:

2 lbs is a single kilo, I do not see the issue. 

 

BMI is a simplistic mathematic formula and makes no claims to be otherwise. 

My point exactly. 

[Kinnock]

Same for me - I think I'm in reasonable shape, run and cycle regularly, no beer belly, look as if I need to eat more (according to my 87 year old Mum ???? ), but BMI puts me just in the overweight section.

Edited November 1, 2019 by Kinnock

[metempsychotic]

1 minute ago, Pilotman said:

My point exactly. 

It is a ball park figure based on averages and can provide a loose indicator of appropriate body mass. 

 

As for 1 kilo, I can fluctuate twice that in a week based on water consumption/retention alone. 

[Pilotman]

2 minutes ago, metempsychotic said:

2 lbs is a single kilo, I do not see the issue. 

 

BMI is a simplistic mathematic formula and makes no claims to be otherwise. 

Ah but it does claim to be the Standard by which we should all measure our selves, or at least many in the medical and nutrition  profession that use it, swear by it.  I can't count the number of times its been trotted out to me and my family over the years, or appears in TV programmes on weight loss and try to find a good book on weight loss that doesn't quote it at some point.  

[Pilotman]

1 minute ago, metempsychotic said:

It is a ball park figure based on averages and can provide a loose indicator of appropriate body mass. 

 

As for 1 kilo, I can fluctuate twice that in a week based on water consumption/retention alone. 

so meaningless then?  I agree. 

[Pattaya46]

I'm curious how a BMI can find you overweight if you are slim ?...

Doctors seem to say BMI works well for most people (average people)

but is known to not be suitable for athletes.

[Tayaout]

BMI is not ideal but it's fast to calculate. 

 

https://www.health.com/weight-loss/waist-circumference-matters-more-than-bmi

 

https://www.omnicalculator.com/health/Waist_Hip

Edited November 1, 2019 by Tayaout

[metempsychotic]

1 minute ago, Kinnock said:

Same for me - I think I'm in reasonable shape, run and cycle regularly, no beer belly, look as if I need to eat more (according to my 87 year old Mum ???? ), but BMI puts just in the obese section.

BMI does not account for muscle mass. Such a small portion of individuals tested is actually physically fit that the generic figures don't account for it. 

 

There are scales that include waist, neck, bicep/tricep and calf thigh measurements that are more accurate. You just need to look for them. 

 

I beleive us navy and army have basic tests that take this into account. 

[Pilotman]

1 minute ago, Pattaya46 said:

I'm curious how a BMI can find you overweight if you are slim ?...

Doctors seem to say BMI works well for most people (average people)

but is known to not be suitable for athletes.

That's a cop out by the medicos.  I am no athlete, but it has no relation to reality for me, or for many others that I know. As another poster said, its an average, a mathematical approximation, which means it is actually relevant to nobody. 

[metempsychotic]

11 minutes ago, Pattaya46 said:

I'm curious how a BMI can find you overweight if you are slim ?...

Doctors seem to say BMI works well for most people (average people)

but is known to not be suitable for athletes.

Exactly. anyone with a high muscle mass should ignore BMI entirely. 

 

Actuall muscle mass is an outdated term, lean body mass is a more current term. That includes muscle and bone etc, everything that is not fat. 

Edited November 1, 2019 by metempsychotic

[metempsychotic]

This might make more sense for some, but it too is overly simplistic. 

 

https://bmi-calories.com/body-fat-percentage-calculator.html

Edited November 1, 2019 by metempsychotic

[evadgib]

11 minutes ago, Pattaya46 said:

I'm curious how a BMI can find you overweight if you are slim ?...

Doctors seem to say BMI works well for most people (average people)

but is known to not be suitable for athletes.

Correct. A marathon-running Paratrooper fell foul of that nonsense some years ago when the MOD laughably dabbled in that direction. 

[Sheryl]

BMI is a screening tool.

 

Like any screening tool it simply flags individuals who need to be assessed more closely to see if there is an issue. And liek any screening tool, there will be false positives. It is better for a screening tool to err in that direction than to miss cases.

 

There isn't another tool of equal simplicity, and there is nothing wrong with using it as a first step in screening.

 

Obviously if it comes up a little overweight on someone who is rippling with muscles and has little body fat, it can be disregarded. I doubt you'd actually get an obese,  as opposed to just overweight, reading from muscle mass alone unless you are a virtual Charles Atlas.  But a muscular man  could easily land in the "overweight" zone.

[Enoon]

 

All the BMI charts I have consulted had accompanying instructions and explanations as to how the readings should be interpreted with regard to age, athleticism, etc.

 

Of necessity they have "hard lines" between categories......normal/overweight/obese, etc.

 

Consequently I am not about to "tear them up" in disgust because I find myself taking the occasional excursion across the normal/overweight "border". 

 

Anyone who is dodging in/out of "obesity" probably should have taken notice a bit earlier though.

 

Perhaps the charts should also contain a special note for that particular brand of censorious, curmudgeonly old man, who spends his time nitpicking, looking for things to complain about, and constantly seeks new horizons of dissatisfaction and disappointment.

 

Yours faithfully,

 

"Will probably have forgotten that it is my 65th birthday by the time it arrives in January"

 

 

 

Edited November 1, 2019 by Enoon

[Lungstib]

My BMI indicates I am well overweight. I laugh it off as just another tool that doesn't always work. Some things you just have to learn not to take too seriously. I am 82Kgs, have a 33 inch waist which is an inch more than 30 years ago when I swam, cycled, trekked up mountains and played football. High blood pressure is far more serious than BMI worries.

[Farangwithaplan]

1 hour ago, Pilotman said:

According to that idiotic measure, the BMI, I am overweight, by 2lbs. It's such a crude measure of weight that I am surprised that anyone takes any notice of it at all.  It destroys the morale of those who are trying to get to a healthy weight, by placed an unrealistic expectation and target for weight loss that takes no account of body shape, lifestyle and fitness.

There is nothing wrong with the calculation when used as it is intended. The issue is that it is used wrongly. BMI is never designed to be used for individuals in the manner you are describing. It is designed for the masses and when used correctly it a fair indicator of a population's body fat percentage. Don't shoot the messenger.

 

I recall a lecturer offering up some examples regarding this very thing. They used a carnival game where people needed to guess the amount of M&Ms or other candy was contained in a glass jar. Individual's guesses were very poor but researchers found that when the mean / average or median (I can't remember which now) was calculated from all the individual guesses, it came out extremely close to the actual figure.

 

I think it is referred to as Collective Wisdom.

 

 

Edited November 1, 2019 by Farangwithaplan

[robblok]

36 minutes ago, Sheryl said:

BMI is a screening tool.

 

Like any screening tool it simply flags individuals who need to be assessed more closely to see if there is an issue. And liek any screening tool, there will be false positives. It is better for a screening tool to err in that direction than to miss cases.

 

There isn't another tool of equal simplicity, and there is nothing wrong with using it as a first step in screening.

 

Obviously if it comes up a little overweight on someone who is rippling with muscles and has little body fat, it can be disregarded. I doubt you'd actually get an obese,  as opposed to just overweight, reading from muscle mass alone unless you are a virtual Charles Atlas.  But a muscular man  could easily land in the "overweight" zone.

I got a high BMI But visible abs and so have many more that do the same sports as I do. So its a bad tool for those of us with some muscles.

 

Its nothing for the average Joe to worry about but those who did sports a lot and or bodybuilding it is not useful. Too bad that many doctors seem to only look at numbers not at how fat someone is.

 

I like the screening tools that use measurements a lot better. 

[Pilotman]

4 minutes ago, Farangwithaplan said:

There is nothing wrong with the calculation when used as it is intended. The issue is that it is used wrongly. BMI is never designed to be used for individuals. It is designed for the masses and when used correctly it a fair indicator of a population's body fat percentage. Don't shoot the messenger.

 

I recall a lecturer offering up some examples regarding this very thing. They used a carnival game where people needed to guess the amount of M&Ms or other candy was contained in a glass jar. Individual's guesses were very poor but researchers found that when the mean / average or median (I can't remember which now) was calculated from all the individual guesses, it came out extremely close to the actual figure.

 

I think it is referred to as Collective Wisdom.

 

 

The messenger is usually a Doctor, Nurse, or other medical/health 'professional', who, as you say, use the 'message' extensively and wrongly.  

[Moonlover]

BMI has been discredited for quite some. According to its calculation I am obese, but that is complete nonsense.

 

But having done some research on this, I've dug out a much more realistic way of assessment, the Smart BMI and you'll find it right here:

 

https://www.smartbmicalculator.com/?ru=0

 

No only does it give you an assessment, there is some follow up dialogue that is very useful as well.

 

Give it a go. You'll never do a old fashioned BMI calculation again.

[Pilotman]

1 hour ago, metempsychotic said:

This might make more sense for some, but it too is overly simplistic. 

 

https://bmi-calories.com/body-fat-percentage-calculator.html

The website is excellent, best I have ever come across and very useful.  Many thanks for posting this.  It has made this post all the more worthwhile.  

[Pilotman]

10 minutes ago, Moonlover said:

BMI has been discredited for quite some. According to its calculation I am obese, but that is complete nonsense.

 

But having done some research on this, I've dug out a much more realistic way of assessment, the Smart BMI and you'll find it right here:

 

https://www.smartbmicalculator.com/?ru=0

 

No only does it give you an assessment, there is some follow up dialogue that is very useful as well.

 

Give it a go. You'll never do a old fashioned BMI calculation again.

another excellent website, many thanks for posting the link. Makes much more sense. 

[Jack Mountain]

BMI doesn't tell you about your weight but about your length ... ???? Today I feel myself a bit short ... after the drinking/food session we had yesterday ...

[Farangwithaplan]

44 minutes ago, Pilotman said:

The messenger is usually a Doctor, Nurse, or other medical/health 'professional', who, as you say, use the 'message' extensively and wrongly.  

I meant me as the messenger ????

 

But I read Sheryl's post and she has some valid points. So I was not altogether correct in my statement when we consider how the health profession use it as a screening tool. But my intention was to say that people use BMI as a factual tool when it is not ever intended to be one.

 

It is really all about people taking the time to become more informed. Poor journalistic reporting, television, and self proclaimed gurus with their own website just increase the gullibility. Applying a little rational thinking and logic to most things, will let us form our own conclusions based on what facts are known. If there aren't enough documented facts, treat it with the skepticism it deserves.

 

 

[metempsychotic]

55 minutes ago, Pilotman said:

The website is excellent, best I have ever come across and very useful.  Many thanks for posting this.  It has made this post all the more worthwhile.  

nice, thanks.

this takes into account even more criteria:

https://www.healthstatus.com/calculate/body-fat-percentage-calculator/

 

[androokery]

1 hour ago, Sheryl said:

BMI is a screening tool.

 

Like any screening tool it simply flags individuals who need to be assessed more closely to see if there is an issue. And liek any screening tool, there will be false positives. It is better for a screening tool to err in that direction than to miss cases.

 

There isn't another tool of equal simplicity, and there is nothing wrong with using it as a first step in screening.

 

Obviously if it comes up a little overweight on someone who is rippling with muscles and has little body fat, it can be disregarded. I doubt you'd actually get an obese,  as opposed to just overweight, reading from muscle mass alone unless you are a virtual Charles Atlas.  But a muscular man  could easily land in the "overweight" zone.

Thank you for being the voice of reason here.

[uhuh]

Large parts of the medical profession did ditch the BMI as OP requested (or never believed in it in the first place).

The revolutionary new idea: look into the mirror to see whether you are fat. 

(I am not kidding)

[stbkk]

On a topical note, I seem to remember that many of the England world cup winning rugby team of 2003 were 'obese' according to BMI, simply because of their large amounts of muscle. I certainly wouldn't have mentioned that to any of them in person...

 

I have an electronic body fat machine (cost about 3,500 Baht at central chitlom a few years ago), which I have a bit more faith in. I don't rely much on the exact measurement, but use it to keep an eye on the direction in which I am moving. Up = bad, down = good!

[justin case]

measure your waist .... 

 

it should be max.  half of your height

 

180 cm height = 90 cm of waist