

Where are you on the global fat scale? - mikecane
http://www.bbc.co.uk/news/health-18770328

======
dredmorbius
BMI is an utterly bogus means of determining _individual_ fitness assessments,
and there's some reason to believe it's not very useful for _population_
measures of fitness.

\- Top 10 Reasons Why The BMI Is Bogus :
[http://www.npr.org/templates/story/story.php?storyId=1062684...](http://www.npr.org/templates/story/story.php?storyId=106268439)

\- Beyond BMI, Why doctors won't stop using an outdated measure for obesity :
<http://www.slate.com/id/2223095/>

\- Do You Believe in Fairies, Unicorns, or the BMI? :
<http://www.maa.org/devlin/devlin_05_09.html>

~~~
dxbydt
Dude, thanks for linking to Dr. Keith Devlin's column. Probably the only thing
I read religiously in the MAA.

BMI is just one of several mistakes attributed to the great mathematician
Quetelet. You can credibly implicate Quetelet for a variety of modern day
statistical crimes such as profiling ( attempting to figure out if a person is
a criminal based on statistical analysis of race/sex/height/etc...),"normal"
age of marriage, statistical rates of divorce in different countries and their
implications on fidelity, and such other sociological nonsense.

Dr. Devlin labels these things "junk math, numerological nonsense". But you
can take a more charitable view - given that Quetelet practically invented
both statistics & sociology ( which he called "physics of society" ), he came
up with a number of formulae that seemed true at that time ( mid 1800s ). On
hindsight much of this stuff is just silly mathematical manipulation ( Instead
of dividing weight by square of height & multiplying by the constant 703, you
can square the weight & divide by the cube root of height and put in some
other constant...) If you are interested in the kind of statistics practiced
in Quetelet's timeframe, here's some wacky references.

[http://en.wikisource.org/wiki/Popular_Science_Monthly/Volume...](http://en.wikisource.org/wiki/Popular_Science_Monthly/Volume_1/May_1872/Quetelet_on_the_Science_of_Man)

[http://statistiks.net/wp-content/plugins/downloads-
manager/u...](http://statistiks.net/wp-content/plugins/downloads-
manager/upload/v0101021.pdf)

btw, much of what we do today in quant finance is suspiciously similar to what
Quetelet suggests :) We build statistical "factor models" that credibly relate
earnings of a company in california to the price of chicken in China :) We
take a rigged number called the LIBOR & price interest rate derivatives on the
spead between this rigged fixed rate & the floating rate. Then the public
loses money & we scream - hey who the fuck rigged the LIBOR in the first place
?:) Talk about bootstrapping... honestly, we are no different from Dr.
Quetelet. Might as well base Google's quarterly earnings on Page's BMI.

~~~
dredmorbius
That's Dr. Dude to you.

Quetelet's work was reasonably appropriate for his time. One source I recall
(cannot find it now) stated that he was looking for a rapid paper-and-pencil
method for estimating aggregate troop strength. As a basic, good-enough first
approximation, BMI works reasonably well. The problem is that it's now been
grossly misapplied.

Quants (and economists) spend, I suspect, a lot of time chasing what turn out
to be transitory relationships between various measurements. The relationships
may very well be statistically valid, when first measured, but either changing
real-world conditions, or, more likely in the financial world, adoption of the
relationships by others seeking profits, rapidly erodes their validity.

Thanks for the links, I've got some reading for later :)

An enterprise I had some association with in the past spent some years and
considerable capital trying to establish a strongly predictive relationship
between a physical property and a health measurement. It turns out that there
_was_ a relationship, but not one which could be reliably used to determine an
accurate quantification of the health measurement. This didn't keep them from
torturing the data extensively.

And Page's health _is_ in the news today:
[http://www.washingtonpost.com/google-ceo-larry-pages-
health-...](http://www.washingtonpost.com/google-ceo-larry-pages-health-is-
much-better/2011/04/07/gJQA6ohBiW_page.html)

------
tfb
I'm really not a fan of BMI being the determining factor in obesity. At 27
BMI, I'm apparently 3 BMI away from being considered obese. As a naturally
large, fairly muscular 24 year old german/irish man, I'm 6 foot 1 and weigh
205 lbs, but you can see my abs and I'm in relatively good physical condition.
Is my definition of obese wrong? I always thought obese meant someone with at
least a few dozen lbs of excess fat.

~~~
streptomycin
Invent a way of easily measuring body fat percentage, and we can do away with
BMI. Until then, muscular people can simply ignore these things. BMI works
well enough for the rest of the population (the vast majority of the world).
If anything, normal people have the opposite problem you do. BMI tends to
underestimate obesity in the general population.
[http://www.cnn.com/2012/04/03/health/obesity-rates-maybe-
wor...](http://www.cnn.com/2012/04/03/health/obesity-rates-maybe-
worse/index.html)

~~~
dredmorbius
A simple waist circumference measurement is more accurate than BMI at making
individual assessments of obesity (> 40" ~ 100cm is bad).

A set of 3-4 tape measurements (height, neck, abdomen for men; height, neck,
waist, hips for women) will give a reasonable estimate of body fat. Equipment
cost, about $5. <http://www.linear-software.com/online.html>

Your observation of the weakness of BMI is that it tends to _misreport_ true
body fat percentage _both_ ways. I'd hardly call that an _advantage_ of BMI.

Note that since official US government policy _defines_ obesity in terms of
BMI, technically, BMI doesn't misreport obesity. What it does is fail to
correspond to true body fat percentage in any meaningful way.

~~~
streptomycin
My point is that BMI is ridiculously easy for nearly everyone to measure.

Your point is that a better measurement can be made if everyone goes out and
buys some new thing and takes some new measurement.

That seems to be in agreement with my point.

> since official US government policy defines obesity in terms of BMI,
> technically, BMI doesn't misreport obesity

The US government defining something doesn't make it true.

>What it does is fail to correspond to true body fat percentage in any
meaningful way.

It is very meaningful. It's much better than a random guess.

~~~
dredmorbius
How are you positing people measure their weight and height without, you know,
like, a scale, and, um, a tape measure?

As many people in the fitness/bodybuilding field will tell you, eyeball
estimates of bodyfat are in fact pretty bloody accurate. If you're interested
in equipment costs, I could look up eyeballs on Amazon as I did for tape
measures.

~~~
streptomycin
Most people know their weight and height already.

And again, I agree that there are more accurate measurements, but they are all
significantly more complicated. This time you are suggesting training people
to visually estimate body fat percentage. That could work. But it's a heck of
a lot more complicated than telling someone to type their height and weight
into a website.

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evilmushroom
This is flawed, very flawed. I weight lift now and workout 6 days a week... in
college I was a skinny 5'11" and 130. I'm not 5'11" and 186.

This is going to tell me I'm fat.

~~~
graeme
Can you see your abs? Serious question.

I hovered around 25 BMI, was muscular, thought it was silly. Everyone
considered me "lean". But, no abs.

Now I can see mine, am very strong, and have a 23 BMI.

It's possible BMI effectiveness changes with height though, which would make
it even worse. I'm 5'6".

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scott_s
This uses the body-mass index, which does _not_ measure fat. It's just a ratio
of height to weight, which does not take _body composition_ into account.

------
gaius
It is really irresponsible of the BBC to be promoting BMI as a measure of
health.

I'm a Marathon runner who is apparently fatter than 99% of the world...

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jere
I hate BMI too (moderately lean according to body fat, but nearly obese
according to BMI).

But whether you're muscular or fat, this scale is a pretty good reminder of
how well nourished we are compared to everyone else.

~~~
mithras
Speak for yourself:

"You're most like someone from DR Congo"

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graeme
They messed up median and average. I'm above the global "average", but if
everyone were like me, the world would lose weight!

They clearly mean I'm heavier than most people, but lighter than the average
BMI. Very large people skew the average upwards.

Edit: I am wrong. See the comment below. I thought average referred to
arithmetic mean.

~~~
dredmorbius
Median _is_ an average measure. As are arithmetic mean and mode.

You're messing up "average" and "mean" :)

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victork2
Before complaining about "wah wah that's BMI, BMI sucks" please think twice.
Everybody knows it's BMI, BMI is a rough measurement of your ratio height to
weight.

[http://en.wikipedia.org/wiki/Body_mass_index#Limitations_and...](http://en.wikipedia.org/wiki/Body_mass_index#Limitations_and_shortcomings)

"The medical establishment has acknowledged major shortcomings of BMI.[...]
found that BMI-defined obesity was present in 21% of men and 31% of women.
Using body fat percentages (BF%), however, BF%-defined obesity was found in
50% of men and 62% of women."

Take it as a statistical game and stop getting self conscious about it.

Note also: If you are very muscular with a crazy BMI despite no fat it's not
healthy either.

~~~
gaius
No "everyone" doesn't know that BMI is discredited, the BBC should have put a
huge disclaimer on it saying "these numbers are nothing to do with how healthy
you are, in fact they are completely meaningless".

~~~
victork2
I like how I got downvoted. Please read everything that is on the website:

The BBC say it's an estimate, with a link on estimate leading to its
definition and a disclaimer about BMI.

They never say that you are fatter or slimmer than the rest of the population
but they talk about your BMI and your BMI only, just a quote:

"You have a lower BMI than 88% of males aged 15-29 in your country"

"You have a lower BMI than 54% of males aged 15-29 in the world"

I really don't see anything about weight or any scheme to make you think
you're fat if you have a high BMI from the BBC like some imply in the
comments. It's very funny how hyper defensive everybody gets around the BMI
thing, especially the ones who don't have the "right" BMI.

------
mathewsanders
Is anyone else having problems with this? I've tried loading in Chrome, Safari
and Firefox and each time a js is not loading and my BMI as '0'

~~~
Tooluka
You probably input Height in centimeters. Try inputting 1.xx (or 2.xx).

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cryptide
>> You're most like someone from Mongolia _

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thekungfuman
I was really interested to see this data until I saw that they use the BMI;
possibly the dumbest and most loudly touted measure of health. According to
these numbers I am overweight, heading towards obese, and I don't think any
doctor on Earth would say I was overweight if they looked at me.

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excuse-me
Damn averages.

By moving to a city with a lot of S.E. Asian people I'm suddenly above average
BMI - I need to move back to Texas.

On the other hand, all those little old Japanese women mean that the average
life expectancy here is among the highest in the world - so I should live to a
100 like them

