Is BMI really BS?

QueenBishOTUniverse

I though you might find this useful.



The National Institutes of Heath did a study called: Accuracy of Body Mass Index to Diagnose Obesity In the US Adult Population

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2877506/

I'm sorry, but to me, this data speaks for itself, the r-squared values are laughable, BMI has almost NO predictive value in establishing how fat you are, and there are a whole hell of a lot of supposedly non existent outliers, on ALL sides of the correlation line. It doesn't tell you how healthy you are, it doesn't tell you how fat you are, all it tells you is how your height and weight compare to everybody else, so what good is it?

Wonderob

That's what's hilarious here. So far there have been almost no true outliers. Just people who are already on the higher end of the "healthy" BMI range, or are just a bit above and, when leaned down, would fall right in line with the "healthy" BMI.

There seems to be an agenda here against those that are overweight on the BMI chart yet refuse to accept they are fat

Too many are saying that overweight people are looking for an excuse to stay fat -maybe so, and I would agree with you on that; however that's got little to do with BMI

You want a true 'outier'? look no further

I am not an athlete, not a bodybuilder, don't look like a running back or Christiano Ronaldo, would consider myself as pretty normal (ok I'm below average height but not freakishly I hope!)

I was:
165lbs
23% BF
BMI = 27.2
= Overweight (and looked and felt it)

Last year
160lbs
16% BF
BMI = 26.3
= Overweight according to BMI - didn't look it, didn't feel it, was told I wasn't overweight

I lost some weight, gained a little muscle - my BMI changed very little.

Mine was just a small transformation from being fat and having no muscle to being not fat and having a little muscle

The BMI charts said my transformation went from being overweight.... to being overweight

http://www.myfitnesspal.com/photos/view/18401123

1saturn

I think BMI has merit at the low end and the really high. It's sketchy at the transition point though. Definitely a good motivator though.

Yeah! That makes sense.

erickirb

I though you might find this useful.



The National Institutes of Heath did a study called: Accuracy of Body Mass Index to Diagnose Obesity In the US Adult Population

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2877506/

I'm sorry, but to me, this data speaks for itself, the r-squared values are laughable, BMI has almost NO predictive value in establishing how fat you are, and there are a whole hell of a lot of supposedly non existent outliers, on ALL sides of the correlation line. It doesn't tell you how healthy you are, it doesn't tell you how fat you are, all it tells you is how your height and weight compare to everybody else, so what good is it?

I don't think it is as bad as you think. It would be nice to show 2 other trend lines above and below the average that are 2 standard deviations from the mean. I bet you would then see where the outliers are... the trend is there and can be noticed, but with a lot of variation, so the lines would be further from the mean, but it is still not that bad of an indicator for the majority of the population

stevencloser

I though you might find this useful.



The National Institutes of Heath did a study called: Accuracy of Body Mass Index to Diagnose Obesity In the US Adult Population

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2877506/

I'm sorry, but to me, this data speaks for itself, the r-squared values are laughable, BMI has almost NO predictive value in establishing how fat you are, and there are a whole hell of a lot of supposedly non existent outliers, on ALL sides of the correlation line. It doesn't tell you how healthy you are, it doesn't tell you how fat you are, all it tells you is how your height and weight compare to everybody else, so what good is it?

I don't think it is as bad as you think. It would be nice to show 2 other trend lines above and below the average that are 2 standard deviations from the mean. I bet you would then see where the outliers are... the trend is there and can be noticed, but with a lot of variation, so the lines would be further from the mean, but it is still not that bad of an indicator for the majority of the population

There's still a difference of 20~% bodyfat between the higher and lower people at the exact same bmi.

Wonderob

I don't think it is as bad as you think. It would be nice to show 2 other trend lines above and below the average that are 2 standard deviations from the mean. I bet you would then see where the outliers are... the trend is there and can be noticed, but with a lot of variation, so the lines would be further from the mean, but it is still not that bad of an indicator for the majority of the population

That's what I keep hearing - The MAJORITY of the population. Or MOST people. Or NORMAL people

So how do you tell? Am I in the majority or not? Is my wife? Are you? If you don't know if the BMI chart is relevant to you then it's useless

Ben_the_builder

I am 5'10" and 240 lbs, my BMI is between 34 and 35 so I am obese. I am half way to the morbid obesity rating. My profile pic/ avatar pic are from about 2 months ago (I weighed 233 lbs in those) so as you can see in those photos I am not fat. BMI is complete garbage. It only factors a height to weight ratio. It does not take body composition into account.

Iwishyouwell

I was:
165lbs
23% BF
BMI = 27.2
= Overweight (and looked and felt it)

Last year
160lbs
16% BF
BMI = 26.3
= Overweight according to BMI - didn't look it, didn't feel it, was told I wasn't overweight

I lost some weight, gained a little muscle - my BMI changed very little.

Mine was just a small transformation from being fat and having no muscle to being not fat and having a little muscle

The BMI charts said my transformation went from being overweight.... to being overweight

http://www.myfitnesspal.com/photos/view/18401123

That's awesome. You are a short man who recomped by putting on a nice amount of muscle mass, and just barely creeping outside the BMI for your shorter height. Congratulations.

You, barely an outlier, have what to do with the general BMI? Most men at your height aren't going to look as ripped as you do at 160 lbs (assuming the after pic isn't wildly flexed).

The funny thing? You're at 16% body fat. Getting athletic lean would land you...right in the "healthy" BMI range. Again, you are just barely an outlier, yet you're the most vehement anti-BMI opponent in this thread.

Wonderob

That's awesome. You are a short man who recomped by putting on a nice amount of muscle mass, and just barely creeping outside the BMI for your shorter height. Congratulations.

You, barely an outlier, have what to do with the general BMI? Most men at your height aren't going to look as ripped as you do at 160 lbs (assuming the after pic isn't wildly flexed).

The funny thing? You're at 16% body fat. Getting athletic lean would land you...right in the "healthy" BMI range. Again, you are just barely an outlier, yet you're the most vehement anti-BMI opponent in this thread.

It doesn't matter what I am though - underweight, normal or overweight it wouldn't alter my view that the BMI chart adds nothing to what people already know. I didn't look at my BMI and realise that I was overweight - there were numerous indicators

Just as now I don't look at my BMI and wonder if I'm overweight - the signs are no longer there

Are there really that many overweight people that don't realise until they see it on a BMI chart?

Mr_Knight

My profile pic/ avatar pic are from about 2 months ago (I weighed 233 lbs in those) so as you can see in those photos I am not fat.

You're not fat.

You are, however, overweight.

Over the long run, that's not healthy, either.

stevencloser

You keep saying "if you push your bf% down you'd be right back in the normal weight" Well obviously they would. That's simple maths And if that isn't enough to get you to normal weight, cut some more fat until you are. But doing that is an exception in itself. The average man is at around 15% bf and not sub 10% or even 5% and a muscular person at this normal amount of bodyfat could easily fall into the overweight category where nonmuscular people with higher bf% are because of the way the bmi ranges were made.

Hornsby

That's awesome. You are a short man who recomped by putting on a nice amount of muscle mass, and just barely creeping outside the BMI for your shorter height. Congratulations.

You, barely an outlier, have what to do with the general BMI? Most men at your height aren't going to look as ripped as you do at 160 lbs (assuming the after pic isn't wildly flexed).

The funny thing? You're at 16% body fat. Getting athletic lean would land you...right in the "healthy" BMI range. Again, you are just barely an outlier, yet you're the most vehement anti-BMI opponent in this thread.

It doesn't matter what I am though - underweight, normal or overweight it wouldn't alter my view that the BMI chart adds nothing to what people already know. I didn't look at my BMI and realise that I was overweight - there were numerous indicators

Just as now I don't look at my BMI and wonder if I'm overweight - the signs are no longer there

Are there really that many overweight people that don't realise until they see it on a BMI chart?

Well, there has already been one in this thread.

jwdieter

See my post on page 5. 153 lbs at 12.2% BF BMI at 26.3%. My lean mass is 134.4 lbs. That would mean in order for me to fit in the BMI normal range I would have to be at 8% BF. I am a woman. I would consider that variance between the 2 to be a clear indication that for me "lose a few pounds and would fall right into the BMI "healthy" range" is irrelevant.

BTW I too have an insurance company that looks at BMI as a way to measure health factors for discounts. Stinks I miss out on that one parameter. Unfortunately I am not willing to lose muscle I have worked to gain to fit the BMI box.

If your measurements are accurate, you're ridiculously off the charts. Are you a professional bodybuilder?

Hornsby

I do not compete, no. I have several friends who do and have gleaned information from them as well as hours and hours of reasearch and trial and error on my own. I have consistently focused on developing muscle while shedding fat since August 2012.

Got any pics?

Wonderob

That's awesome. You are a short man who recomped by putting on a nice amount of muscle mass, and just barely creeping outside the BMI for your shorter height. Congratulations.

You, barely an outlier, have what to do with the general BMI? Most men at your height aren't going to look as ripped as you do at 160 lbs (assuming the after pic isn't wildly flexed).

The funny thing? You're at 16% body fat. Getting athletic lean would land you...right in the "healthy" BMI range. Again, you are just barely an outlier, yet you're the most vehement anti-BMI opponent in this thread.

It doesn't matter what I am though - underweight, normal or overweight it wouldn't alter my view that the BMI chart adds nothing to what people already know. I didn't look at my BMI and realise that I was overweight - there were numerous indicators

Just as now I don't look at my BMI and wonder if I'm overweight - the signs are no longer there

Are there really that many overweight people that don't realise until they see it on a BMI chart?

Well, there has already been one in this thread.

You're unlikely to look at a BMI calculator if you don't suspect that you are overweight. If you're borderline overweight then the BMI chart is of little value. If you're significantly overweight then most will already know

That person in question went on to say that they also looked at a number of other indicators too including BF to establish if they were overweight

jwdieter

I do not compete, no. I have several friends who do and have gleaned information from them as well as hours and hours of reasearch and trial and error on my own. I have consistently focused on developing muscle while shedding fat since August 2012.

Well, you've apparently managed to achieve a higher relative muscle mass than Iris Kyle (8x Ms Olympia), so that's.. something.

sodakat

The U.S. D.O.T (department of transportation) implemented new guidelines for CD (commercial drivers license) holders specifically aimed at over the road truckers. If our BMI is 35 or higher a sleep apnea test can be required and if OSA is diagnosed the use of a CPAP machine can be mandated along with periodic checkups and further testing. My doctor told me last month that she was going to be forced to cause big round guys to lose their jobs. Her words. She's been administering DOT physicals for 20 years and this is a huge change requiring all doctors be re certified and training ed to give the physical.

jwdieter

I don't share pictures. My response was in an effort to point out that there are people that are outside of the average BMI and losing a few pounds isn't a realsitic option. I am not any sort of professional and was making that point that for me the BMI chart is not accurate.

The problem with what you're saying is like me saying I'm a natural 5'10 270 with shredded lower glutes. You're claiming 10% lower body fat than any woman with similar BMI on the study quoted many times in this thread. It's simply not believable, so your point isn't particularly strong.

Iwishyouwell

That's awesome. You are a short man who recomped by putting on a nice amount of muscle mass, and just barely creeping outside the BMI for your shorter height. Congratulations.

You, barely an outlier, have what to do with the general BMI? Most men at your height aren't going to look as ripped as you do at 160 lbs (assuming the after pic isn't wildly flexed).

The funny thing? You're at 16% body fat. Getting athletic lean would land you...right in the "healthy" BMI range. Again, you are just barely an outlier, yet you're the most vehement anti-BMI opponent in this thread.

It doesn't matter what I am though - underweight, normal or overweight it wouldn't alter my view that the BMI chart adds nothing to what people already know. I didn't look at my BMI and realise that I was overweight - there were numerous indicators

Just as now I don't look at my BMI and wonder if I'm overweight - the signs are no longer there

Are there really that many overweight people that don't realise until they see it on a BMI chart?

I already told you. Me. Let me tell you what else the BMI taught me.

When I was in my 180s, looking good in clothes, but with a ton of fat still left on my trunk, looking at charts helped me realize that I wasn't really "big boned", and the weight ranges given were dead on for me if I wanted to be leaner.

The weight I had left was flabby and deflated looking. Many people would call it "loose skin". Deciding to continue cutting down lower into the previously, seemingly unrealistic ranges in the BMI charts actually taught me a very valuable lesson about excess/loose skin. A lot of the times it's just fat that can still be lost. If I hadn't paid attention to that, and continued to consider myself a big boned outlier who couldn't, or shouldn't, really get below my upper 180s, I'd have been one of these many still too-fat people walking around screaming about how much "loose skin" they still have.

The BMI charts were a huge eye opener to me about proper weight for myself, and many people. Realizing that the men of my dad and granddad's generation were, in general, well within those ranges back before the obesity crisis helped give me a lot of perspective.

bennettinfinity

I though you might find this useful.



The National Institutes of Heath did a study called: Accuracy of Body Mass Index to Diagnose Obesity In the US Adult Population

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2877506/

I'm sorry, but to me, this data speaks for itself, the r-squared values are laughable, BMI has almost NO predictive value in establishing how fat you are, and there are a whole hell of a lot of supposedly non existent outliers, on ALL sides of the correlation line. It doesn't tell you how healthy you are, it doesn't tell you how fat you are, all it tells you is how your height and weight compare to everybody else, so what good is it?

I don't think it is as bad as you think. It would be nice to show 2 other trend lines above and below the average that are 2 standard deviations from the mean. I bet you would then see where the outliers are... the trend is there and can be noticed, but with a lot of variation, so the lines would be further from the mean, but it is still not that bad of an indicator for the majority of the population

That's not how scatter plots work - the r-squared value indicates the data's predictive power. An r-square of 0.7 is considered a weak correlation, and only a fool would attempt to make predictions with an r-square below a 0.5. At best the plots show that NEWSFLASH! weight is correlated with height... really? Tall people generally weigh more than short people? Who'da thunk it?