Is BMI really BS?

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.

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.

Yes. Funny how most of the people in this thread who are arguing are sporting higher relative masses than your typical competitor and Olympian.

Snowflakes are falling.

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

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?

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?

Seriously, my jaw dropped when I saw those graphs, worthless metric is worthless, which is why I can't even go along with the OK for most argument any more.

I agree and said that earlier, doesn't change the fact that for indicating obesity, it's virtually worthless, so again, what IS it good for?

I agree and said that earlier, doesn't change the fact that for indicating obesity, it's virtually worthless, so again, what IS it good for?

If you're BMI obese, you're very likely to actually be body fat obese. So that's what it's good for.

I agree and said that earlier, doesn't change the fact that for indicating obesity, it's virtually worthless, so again, what IS it good for?

If you're BMI obese, you're very likely to actually be body fat obese. So that's what it's good for.

But it doesn't capture a whole slew of people who are actually obese, but will never know it because BMI says they're healthy, and skews drastically in the other direction for women as you approach healthy BMI. And as another poster has already pointed out, if you classify as obese on both BF and BMI, chances are you already know you have a weight issue and probably don't need BMI to tell you that.

For studies of the general population BMI is a useful tool as all you need are everyone's weight and height, easy measures to obtain.

For an individual, it could potentially be very inaccurate.

I agree and said that earlier, doesn't change the fact that for indicating obesity, it's virtually worthless, so again, what IS it good for?

If you're BMI obese, you're very likely to actually be body fat obese. So that's what it's good for.

But it doesn't capture a whole slew of people who are actually obese, but will never know it because BMI says they're healthy, and skews drastically in the other direction for women as you approach healthy BMI. And as another poster has already pointed out, if you classify as obese on both BF and BMI, chances are you already know you have a weight issue and probably don't need BMI to tell you that.

umm....unless they were looking at the wrong range of BMI...real obese with a healthy BMI is almost unlikely. The other way around (higher BMI but healthy muscle/fat ratio) is possible, which a lot of posters were trying to convince the others with their outlier examples...

For me, it is. I was overweight and excuse my french, sexy as fuark. Softened up a bit, because I didn't feel the need to look the the terminator while not competing.

For most of the population, no. It's a perfectly acceptable standard for the average person with a normal amount of muscle mass.

For me, it is. I was overweight and excuse my french, sexy as fuark. Softened up a bit, because I didn't feel the need to look the the terminator while not competing.

For most of the population, no. It's a perfectly acceptable standard for the average person with a normal amount of muscle mass.

And where are the charts to find out if you're an average person? I thought I was but I'm classified as overweight according to BMI

Average as in...you don't have enough muscle to be clinically overweight while having a single digit body fat. For men at least. If the BMI scale says you're fat, and you're body fat percentage says you're fat, you are average, and not the exception to the norm.