improved BMI?

[David L. Johnson]

On Sun, 04 Dec 2005 18:12:31 -0600, jbuch wrote:

> Take a 7 foot person and a 5 foot person.
>
> Would you expect the 5 foot person of "normal build" to have a waist
> which is 5/7 of that for a 7 foot tall person?
>
> This linear relationship is what happens if the height^3 (cubed) scaling
> law is assumed..... But, if you understood the topic, you would have
> known that.
>
> Taking the 34 inch waist for the 7 foot person as "fit physique", would
> you expect the waist of the 6 foot person to be 24.3 inches (5/7 of 34
> is 24.3 inches) for a "fit physique"?

Oops. Here you said a 6-foot person, but used the ratio between a 5 and
7 foot person.

Your 7-footer with a 34-inch waist would be proportional to a 6-footer
with a 29-inch waist. Now, most of us don't know a whole lot of
7-foot-tall people, but we do know 6-footers, and a 29" waist is fairly
thin, but not anorexic. A proportional 5-footer would have that 24"
waist, also just fairly thin, for a 5-foot person. I think your
assumption that a "fit" 7-foot person should have a 34-inch waist is an
underestimate.

> And if you go into a clothing store that deals in short people's
> clothes, you would find a range of waist sizes that you could use to
> better calibrate the scaling law that actually fits the body
> configurations that humans have.

But, BMI scales "show" that well over half of Americans are "overweight",
so knowing what size people _are_ would not be a measure of what they
shyould be.

The scaling used in BMI was obtained from data of 20-30 year-olds, and
that data is used as the standard to which 50-year olds are told to aspire
to.

> person of "nominal physique" ( with a 7 foot 34 inch waist as "nominal
> physique for reference)

Your assumption that a 7-foot tall person with a 34-inch waist is the
proper reference is absurd. How about a 6-foot tall person with a 32-inch
waist? That is still a rather thin build.

--

David L. Johnson

__o | "A foolish consistency is the hobgoblin of little minds, adored
_`\(,_ | by little statesmen and philosophers and divines." --Ralph Waldo
(_)/ (_) | Emerson

 

[David L. Johnson]

On Sun, 04 Dec 2005 20:16:44 +0000, Jasper Janssen wrote:

> Because height^3 leads to massive aberrancies even within the normal human
> healthy range of between a bit under 5 feet and 6.5 feet, more so than
> than ^2 does. Empirically determined.

Determined by a single study 20+ years ago of people between 20 and 30
years old.

> Basically it's because smaller or
> taller doesn't mean everything on your body scales in depth and width
> equally. Look at genetic dwarves, or the vertically challenged, or
> whatever the current PC term is: they're still very nearly as wide and
> deep as the average human, just shorter (which makes them look wildly
> out of proportion).

Actually, the reason they look "wildly out of proportion" is that their
limbs _are_ out of proportion to their trunk and head sizes, not simply
because they are smaller.

> Similarly, NBA players aren't wider or deeper in
> proportion to their excessive height, which also makes them look wildly
> out of proportion.

Depends on who you are looking at. Shaquille O'Neill, scaled down to
6-feet tall, would look pretty normal, though Michael Jordan would look
thin.

--

David L. Johnson

__o | The lottery is a tax on those who fail to understand
_`\(,_ | mathematics.
(_)/ (_) |

 

[O-V R:nen]

"David L. Johnson" <[email protected]> writes:

> It also says, and I quote:

> "If one animal is, say, twice as big as another animal in each linear
> dimension, then its total volume, or mass, is 23 times as large, but its
> skin surface is only 22 times as large."

> Umm, no. If one animal is proportionally twice as big as another in each
> linear dimension (presuming 3-dimensional animals, here), it would have 8
> times the volume, and 4 times the skin surface.

"23" should clearly be 2^3 and "22" 2^2.

 

[Robert Chung]

jbuch wrote:

> Taking the 34 inch waist for the 7 foot person as "fit physique"

At 7'1" and 13% bodyfat, Shaq has a 54 inch waist.

 

[jbuch]

David L. Johnson wrote:
> On Sun, 04 Dec 2005 18:12:31 -0600, jbuch wrote:
>
>
>>Take a 7 foot person and a 5 foot person.
>>
>>Would you expect the 5 foot person of "normal build" to have a waist
>>which is 5/7 of that for a 7 foot tall person?
>>
>>This linear relationship is what happens if the height^3 (cubed) scaling
>>law is assumed..... But, if you understood the topic, you would have
>>known that.
>>
>>Taking the 34 inch waist for the 7 foot person as "fit physique", would
>>you expect the waist of the 6 foot person to be 24.3 inches (5/7 of 34
>>is 24.3 inches) for a "fit physique"?
>
>
> Oops. Here you said a 6-foot person, but used the ratio between a 5 and
> 7 foot person.

Mistyped a 6 for a 5 in discussing the 5 foot man.

I am sure it was too hard for you to figure that one oout, because of
your intense negativity.

Bye.

<snip>

 

[Jasper Janssen]

On 4 Dec 2005 16:02:43 -0800, "Chalo" <[email protected]> wrote:

>
>The statistically flawed nature of BMI is in common with height/weight
>tables and other such contrivances, but its geometrical flaw insures
>that the further you deviate from the statistical mean, the more
>inaccurate it becomes as an indicator of health or body composition.
>
>If it were only the province of the quacks who created it, then it
>would not be a problem. The trouble comes when insurers and medical
>professionals treat as if it had any scientific value.

I certainly am not claiming that h^2 has any magical properties, all I'm
saying is that it's better than h^3. I don't particularly like either
variant, because of all the reasons you mention.

Jasper

 

[Phil Holman]

"Jasper Janssen" <[email protected]> wrote in message
news:[email protected]...
> On Fri, 02 Dec 2005 10:21:12 GMT, Dan Connelly
> <d_j_c_o_n_n_e_l@i_e_e_e.o_r_g> wrote:
>
>>However, I suspect people have enough trouble grasping units of
>>"kg/m^2",
>>trying to get them to swallow "kg/m^2.2" may perhaps be a bit much.
>>But
>>there seems a strong case to be made that the BMI index is "unfair" to
>>tall
>>people (assuming lower is better, usually the case among those with
>>enough
>>income to read this message).
>
> Personally, I don't need a fricking calculator to tell me I'm
> overweight.
> I'd be much better off at two thirds or a bit oover half my current
> weight, but according to Quetelet/BMI I'd still be overweight then,
> which
> would clearly not be the case.

I don't need no steeeeenkin formula to tell me if I'm overweight. All I
need is a big mirror. Yes, thats the ticket, BMI = big mirror index.

Phil H

 

[Ryan Cousineau]

In article <[email protected]>,
"David L. Johnson" <[email protected]> wrote:

> On Sun, 04 Dec 2005 18:12:31 -0600, jbuch wrote:
>
> > You can find some information on scaling laws for animals here....
> > 1) http://smccd.net/accounts/goth/other/Life_On_The_Scales.pdf
> > 2) http://www.primidi.com/2005/02/21.html
> > and it is a tad technical.
>
> "Technical" is an interesting term, here. From the first site, it
> suggests that all animals have basically the same number of heartbeats in
> a lifetime; that metabolic rate is proportional to mass. But humans live
> longer than elephants. Oops.

No, that's a well-known quirk. Humans live unusually long; among the
longest of all animals, and considerably longer than anything about the
same size as ourselves (deer, some big cats, certain primates: pick your
favorite).

--
Ryan Cousineau [email protected] http://www.wiredcola.com/
"I don't want kids who are thinking about going into mathematics
to think that they have to take drugs to succeed." -Paul Erdos

 

[David L. Johnson]

On Tue, 06 Dec 2005 04:09:02 +0000, Ryan Cousineau wrote:

> In article <[email protected]>,
> "David L. Johnson" <[email protected]> wrote:
>
>> On Sun, 04 Dec 2005 18:12:31 -0600, jbuch wrote:
>>
>> > You can find some information on scaling laws for animals here....
>> > 1) http://smccd.net/accounts/goth/other/Life_On_The_Scales.pdf
>> > 2) http://www.primidi.com/2005/02/21.html
>> > and it is a tad technical.
>>
>> "Technical" is an interesting term, here. From the first site, it
>> suggests that all animals have basically the same number of heartbeats in
>> a lifetime; that metabolic rate is proportional to mass. But humans live
>> longer than elephants. Oops.
>
> No, that's a well-known quirk. Humans live unusually long; among the
> longest of all animals, and considerably longer than anything about the
> same size as ourselves (deer, some big cats, certain primates: pick your
> favorite).

Parrots are considerably smaller, but tend to live longer than humans.
people who own parrots often make arrangement for their care in their
wills. I think there are so many "exceptions that prove the rule" that
the exceptions, rather than proving the rule, make it seem inaccurate.

--

David L. Johnson

__o | Accept risk. Accept responsibility. Put a lawyer out of
_`\(,_ | business.
(_)/ (_) |

 

[Robert Chung]

Jasper Janssen wrote:

> Personally, I don't need a fricking calculator to tell me I'm
> overweight. I'd be much better off at two thirds or a bit oover half my
> current weight, but according to Quetelet/BMI I'd still be overweight
> then, which would clearly not be the case.

Your current BMI is up around 40?

 

[Robert Chung]

Phil Holman wrote:
> I don't need no steeeeenkin formula to tell me if I'm overweight. All I
> need is a big mirror. Yes, thats the ticket, BMI = big mirror index.

"T'es affute, toi, mon salopard. Pas un pet de graisse."

 

[Phil Holman]

"Robert Chung" <[email protected]> wrote in message
news:[email protected]...
> Phil Holman wrote:
>> I don't need no steeeeenkin formula to tell me if I'm overweight. All
>> I
>> need is a big mirror. Yes, thats the ticket, BMI = big mirror index.
>
> "T'es affute, toi, mon salopard. Pas un pet de graisse."
>

Oh yeh, Ilan's Grande Boucle "You are one fit son of a *****. Not one
once of fat"

Phil H

 

[Ryan Cousineau]

In article <[email protected]>,
"David L. Johnson" <[email protected]> wrote:

> On Tue, 06 Dec 2005 04:09:02 +0000, Ryan Cousineau wrote:
>
> > In article <[email protected]>,
> > "David L. Johnson" <[email protected]> wrote:
> >
> >> On Sun, 04 Dec 2005 18:12:31 -0600, jbuch wrote:
> >>
> >> > You can find some information on scaling laws for animals here....
> >> > 1) http://smccd.net/accounts/goth/other/Life_On_The_Scales.pdf
> >> > 2) http://www.primidi.com/2005/02/21.html
> >> > and it is a tad technical.
> >>
> >> "Technical" is an interesting term, here. From the first site, it
> >> suggests that all animals have basically the same number of heartbeats in
> >> a lifetime; that metabolic rate is proportional to mass. But humans live
> >> longer than elephants. Oops.
> >
> > No, that's a well-known quirk. Humans live unusually long; among the
> > longest of all animals, and considerably longer than anything about the
> > same size as ourselves (deer, some big cats, certain primates: pick your
> > favorite).
>
> Parrots are considerably smaller, but tend to live longer than humans.
> people who own parrots often make arrangement for their care in their
> wills. I think there are so many "exceptions that prove the rule" that
> the exceptions, rather than proving the rule, make it seem inaccurate.

No, you just remember the exceptions. For every parrot, there's a few
thousand bird species with lifespans shorter than the average boy band's
popularity. But as with boy bands, there are outliers in the bird world,
too.

The PDF has some details about how body temperature is another key
factor: it seems to be a straight proxy for metabolic rate, more or less.

--
Ryan Cousineau [email protected] http://www.wiredcola.com/
"I don't want kids who are thinking about going into mathematics
to think that they have to take drugs to succeed." -Paul Erdos

 

[David L. Johnson]

>> Parrots are considerably smaller, but tend to live longer than humans.
>> people who own parrots often make arrangement for their care in their
>> wills. I think there are so many "exceptions that prove the rule" that
>> the exceptions, rather than proving the rule, make it seem inaccurate.
>
> No, you just remember the exceptions. For every parrot, there's a few
> thousand bird species with lifespans shorter than the average boy band's
> popularity. But as with boy bands, there are outliers in the bird world,
> too.
>
> The PDF has some details about how body temperature is another key
> factor: it seems to be a straight proxy for metabolic rate, more or less.

It is basically poor science to throw out as "bad data" anything that does
not conform to your theory, and that is what I see in that article.

--

David L. Johnson

__o | Let's not escape into mathematics. Let's stay with reality. --
_`\(,_ | Michael Crichton
(_)/ (_) |

 

[Jasper Janssen]

On Tue, 6 Dec 2005 06:29:23 +0100, "Robert Chung" <[email protected]>
wrote:
>Jasper Janssen wrote:
>
>> Personally, I don't need a fricking calculator to tell me I'm
>> overweight. I'd be much better off at two thirds or a bit oover half my
>> current weight, but according to Quetelet/BMI I'd still be overweight
>> then, which would clearly not be the case.
>
>Your current BMI is up around 40?

Not quite, but fairly close.

Jasper

 

[Jasper Janssen]

On Sun, 04 Dec 2005 19:19:05 -0600, jbuch <[email protected]>
wrote:

>When I was fat enough, I floated nicely.

Be safe: be fat.

Jasper

 

[Dave Lehnen]

David L. Johnson wrote:

<snip>
>
>
> Parrots are considerably smaller, but tend to live longer than humans.
> people who own parrots often make arrangement for their care in their
> wills. I think there are so many "exceptions that prove the rule" that
> the exceptions, rather than proving the rule, make it seem inaccurate.
>

The exceptions prove the rule when the intended meaning of the word
"prove" is used: Merriam-Webster, "to test the truth, validity or
genuineness of". In this case, the many exceptions may prove the rule
and find it lacking. This adage is commonly misunderstood to mean that
somehow an exception to a rule causes the rule to be valid, which makes
little sense.

Also, I have it on good authority that dead parrots can be nailed to
their perches by unscrupulous pet shops, extending their salable lives.

Dave Lehnen

 

[Mark Hickey]

"David L. Johnson" <[email protected]> wrote:

>On Tue, 06 Dec 2005 04:09:02 +0000, Ryan Cousineau wrote:

>> No, that's a well-known quirk. Humans live unusually long; among the
>> longest of all animals, and considerably longer than anything about the
>> same size as ourselves (deer, some big cats, certain primates: pick your
>> favorite).
>
>Parrots are considerably smaller, but tend to live longer than humans.
>people who own parrots often make arrangement for their care in their
>wills. I think there are so many "exceptions that prove the rule" that
>the exceptions, rather than proving the rule, make it seem inaccurate.

Only some of 'em though.

We had an African Gray for a couple years (the bird flew into our back
yard, and we were never able to find the owner). When we discovered
that a bird that looks like a pigeon with a parrot mask can live 55
years, and that ours was "only" 4-7 years old, we decided that we
would find a new home for it.. ;-)

Actually we did so because the thing was TOO smart for our own good -
it took a huge amount of time to keep it intellectually stimulated.
I've never seen a parrot learn SO much language SO fast - he'd put
together sentences we didn't teach it... scary. We ended up giving
it to a doctor who had converted half his house into an aviary, and
who had another Gray without a buddy. Worked out great.

Other parrots (generally the larger ones) can live 80 or more years.
Unless you have cats. ;-)

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame