Body mass index - reliable?

[Tim Cain]

Hi,

I calculated my BMI today (6", 16st10lb), and came up with
a BMI of 31.5, which puts me fairly well into the "Obese
type I" camp.

This seems bizarre - I don't look fat, and I'm the fastest out
of all my regular cycling buddies (especially on hill climbs)
during 30+ mile rides.

Is the BMI based on some "average" build or something like
that? Or am I just an unwitting fat git?

Best,

Tim.

[Vic]

"Tim Cain" <tcain@you_know_what_to_cut_clara.co.uk> wrote in
message news:<1031686550.10377.0@doris.uk.clara.net>...
> Hi,
>
> I calculated my BMI today (6", 16st10lb), and came up with a
> BMI of 31.5, which puts me fairly well into the "Obese type
> I" camp.
>
> This seems bizarre - I don't look fat, and I'm the fastest
> out of all my regular cycling buddies (especially on hill
> climbs) during 30+ mile rides.
>
> Is the BMI based on some "average" build or something like
> that? Or am I just an unwitting fat git?
>

Some current thinking indicates that it is possible to be both
fat and fit: The health risks of being overweight are
associated with inactivity and poor diet, rather than the
extra weight per se.

My personal jury is still out on this idea, though.

Vic.

[Pbeyer]

Tim Cain wrote:

> Hi,
>
> I calculated my BMI today (6", 16st10lb), and came up with a
> BMI of 31.5, which puts me fairly well into the "Obese type
> I" camp.
>
> This seems bizarre - I don't look fat, and I'm the fastest
> out of all my regular cycling buddies (especially on hill
> climbs) during 30+ mile rides.
>
> Is the BMI based on some "average" build or something like
> that? Or am I just an unwitting fat git?
>
> Best,
>
> Tim.

Tim-- BMI is likely "reliable" in that each time you measure
it, you sjpi;d get the same result-- Does it accurately
refluct your body fat or your health risk? Not necessarily. If
you have concerns or doubts because you are fit, you can have
your body fat measured by a number of methods to see if you
have a high ratio of lean body mass to fat mass. BMI is a
valuable screening tool but especally at the <35 range it is
just that. You could also check your waist size (less than 40
inches? or waist: hip ratio (1 or less?) Pete

[Eric Bohlm]

victor_papanek@hotmail.com (Vic) wrote in
news:2fa8fe91.0209110430.32ab8853@posting.google.com:

> Some current thinking indicates that it is possible to be
> both fat and fit: The health risks of being overweight are
> associated with inactivity and poor diet, rather than the
> extra weight per se.
>
> My personal jury is still out on this idea, though.

There's also the issue of where the fat is stored in the body.
It seems that fat stored in the abdomen, especially internally
around the abdominal organs, has worse effects than fat stored
under the skin peripherally. I think the working hypothesis is
that visceral fat has access to the portal circulation and the
higher levels of FFAs/triglycerides entering the liver have
negative metabolic effects.

[L. Fuellem]

> I calculated my BMI today (6", 16st10lb), and came up with a
> BMI of 31.5, which puts me fairly well into the "Obese type
> I" camp.
>
> This seems bizarre - I don't look fat, and I'm the fastest
> out of all my regular cycling buddies (especially on hill
> climbs) during 30+ mile rides.
>
> Is the BMI based on some "average" build or something like
> that? Or am I just an unwitting fat git?

BMI (Body Mass Index) is simply a ratio of a person's body
weight to height (weight in kg divided by the square of height
in meters). According to the CDC (see
http://www.cdc.gov/nccdphp/dnpa/bmi/), it is "more highly
correlated with body fat than any other indicator of height
and weight (NRC
p563)".

However, it is only a "correlation". There are always people
outside the norm. For example, if a person is extremely
muscular or has a large frame, then their weight will be
higher for their height and their BMI will read in the
"overweight" or even "obese" range.

Personally, I think the important question is not "Am I
overweight?", but "Am I overfat?". Again, everyone is
different, but many sources have shown that healthy body fat
percentages are between 10 and 18 percent for men and 18 to 25
percent for women. Athletes are frequently considerably lower
than that.

Is order to determine if you're "overfat" and thus have health
risks, you should determine your body fat percentage. There
are many ways to do this, though the most accurate will cost
and require you to visit a clinic of some sort. The most
common methods are: anthropometry (skin fold analysis),
bioelectrical impedance, and near-infrared interactance. These
are the easiest to come across, but may have questionable
accuracy depending on the quality of the equipment and the
skills of the administrator. The most accurate (and expensive)
methods are hydrostatic weighing and DEXA.

A quick test to whether or not you're "overfat" is, "can you
pinch an inch"? (Meaning, at your waistline, on your side,
grab your flesh between your thumb and forefinger and see if
you have more than an inch.) Another quick test is one you've
already performed and passed: the "do I look fat" test. If you
don't have parts that wiggle or jiggle (when they shouldn't),
then you're probably not overfat. Definitely not scientific,
but fairly accurate.

Good luck & don't get stuck on numbers.

Regards,

--Lisa

[Ron Ritzma]

Tim Cain <tcain@you_know_what_to_cut_clara.co.uk> wrote:
> Hi,

> I calculated my BMI today (6", 16st10lb), and came up with a
> BMI of 31.5, which puts me fairly well into the "Obese type
> I" camp.

> This seems bizarre - I don't look fat,

Tell me about it. My BMI is about the same but look at the
"after" pictures in the URL in my sig. Do I look obese?

--
Ron Ritzman http://www.panix.com/~ritzlart Smart people can
figure out my email address

[Tim Cain]

"Vic" <victor_papanek@hotmail.com> wrote in message
news:2fa8fe91.0209110430.32ab8853@posting.google.com...
> "Tim Cain" <tcain@you_know_what_to_cut_clara.co.uk> wrote
> in message
news:<1031686550.10377.0@doris.uk.clara.net>...
> > Hi,
> >
> > I calculated my BMI today (6", 16st10lb), and came up with
> > a BMI of 31.5, which puts me fairly well into the "Obese
> > type I" camp.
> >
> > This seems bizarre - I don't look fat, and I'm the fastest
> > out of all my regular cycling buddies (especially on hill
> > climbs) during 30+ mile rides.
> >
> > Is the BMI based on some "average" build or something like
> > that? Or am I just an unwitting fat git?
> >
>
> Some current thinking indicates that it is possible to be
> both fat and fit: The health risks of being overweight are
> associated with inactivity and poor diet, rather than the
> extra weight per se.
>
> My personal jury is still out on this idea, though.
>
> Vic.

I don't know wether this has any bearing on the issue, but I
do have absurdly developed legs!

ie. I can get trousers that fit me comfortably around the
waist, but they are way too tight around my thighs (which
are muscular, rather than fat). I have to wear the
baggiest "leisure pants" I can find. BTW, my waist is 36".

Keep on truckin'

Tim.

[End User]

In article <1031771836.63505.0@iris.uk.clara.net>, Tim
Cain wrote:
>
> "Vic" <victor_papanek@hotmail.com> wrote in message
> news:2fa8fe91.0209110430.32ab8853@posting.google.com...
>> "Tim Cain" <tcain@you_know_what_to_cut_clara.co.uk> wrote
>> in message
> news:<1031686550.10377.0@doris.uk.clara.net>...
>> > Hi,
>> >
>> > I calculated my BMI today (6", 16st10lb), and came up
>> > with a BMI of 31.5, which puts me fairly well into the
>> > "Obese type I" camp.
>> >
>> > This seems bizarre - I don't look fat, and I'm the
>> > fastest out of all my regular cycling buddies (especially
>> > on hill climbs) during 30+ mile rides.
>> >
>> > Is the BMI based on some "average" build or something
>> > like that? Or am I just an unwitting fat git?
>> >
>>
>> Some current thinking indicates that it is possible to be
>> both fat and fit: The health risks of being overweight are
>> associated with inactivity and poor diet, rather than the
>> extra weight per se.
>>
>> My personal jury is still out on this idea, though.
>>
>> Vic.
>
> I don't know wether this has any bearing on the issue, but I
> do have absurdly developed legs!
>
> ie. I can get trousers that fit me comfortably around the
> waist, but they are way too tight around my thighs
> (which are muscular, rather than fat). I have to wear
> the baggiest "leisure pants" I can find. BTW, my waist
> is 36".
>
> Keep on truckin'
>
> Tim.
>
One thing you should consider is your bone structure; the BMI
totally ignores it.

If you have a dense bone structure and/or have large bones,
the "excess" weight you see could be due to the bones and not
fat; I like to think that is the reason I sink instead of
float in fresh water.

There is a book called "Total Nutrition" that is comprised of
writings by various doctors and a way to measure for bone size
is the width of the elbow bone(?) when the arm is bent at
right angles with the elbow forming the angle. Have no idea
how accurate this way of finding one's bone size is but it
does help me feel better about my BMI of 29 :_).

[Ron Ritzma]

Eric Bohlman <ebohlman@omsdev.com> wrote:

> There's also the issue of where the fat is stored in the
> body. It seems that fat stored in the abdomen, especially
> internally around the abdominal organs, has worse effects
> than fat stored under the skin peripherally. I think the
> working hypothesis is that visceral fat has access to the
> portal circulation and the higher levels of
> FFAs/triglycerides entering the liver have negative
> metabolic effects.

That might explain why some fat people see a marked
improvement in their health when they lose weight, even if
still technically obese. Visceral fat, being the most
metabolically active would usually be the first fat lost
on a diet.

--
Ron Ritzman http://www.panix.com/~ritzlart Smart people can
figure out my email address

[Daniel Isr]

"L. Fuellemann" <fuellemann@process.com> wrote in message
news:alobi4$6dd$1@news.process.com...
> BMI (Body Mass Index) is simply a ratio of a person's body
> weight to
height
> (weight in kg divided by the square of height in meters).
> According to
the
> CDC (see http://www.cdc.gov/nccdphp/dnpa/bmi/), it is "more
> highly correlated with body fat than any other indicator of
> height and weight
(NRC
> p563)".
>
> However, it is only a "correlation". There are always people
> outside the norm. For example, if a person is extremely
> muscular or has a large
frame,
> then their weight will be higher for their height and their
> BMI will read
in
> the "overweight" or even "obese" range.
>
> Personally, I think the important question is not "Am I
> overweight?", but "Am I overfat?". Again, everyone is
> different, but many sources have
shown
> that healthy body fat percentages are between 10 and 18
> percent for men
and
> 18 to 25 percent for women. Athletes are frequently
> considerably lower
than
> that.
>
> Is order to determine if you're "overfat" and thus have
> health risks, you should determine your body fat percentage.
> There are many ways to do
this,
> though the most accurate will cost and require you to visit
> a clinic of
some
> sort. The most common methods are: anthropometry (skin fold
> analysis), bioelectrical impedance, and near-infrared
> interactance. These are the easiest to come across, but may
> have questionable accuracy depending on
the
> quality of the equipment and the skills of the
> administrator. The most accurate (and expensive) methods are
> hydrostatic weighing and DEXA.
>
> A quick test to whether or not you're "overfat" is, "can you
> pinch an
inch"?
> (Meaning, at your waistline, on your side, grab your flesh
> between your thumb and forefinger and see if you have more
> than an inch.) Another quick test is one you've already
> performed and passed: the "do I look fat"
test.
> If you don't have parts that wiggle or jiggle (when they
> shouldn't), then you're probably not overfat. Definitely not
> scientific, but fairly accurate.
>
> Good luck & don't get stuck on numbers.

Problem is, some people (read: the insurance companies) are
stuck on the numbers. They don't care what it looks like, they
only care about the number on the paper. (It's probably some
fat guy in Connecticut making the decision...) Not only that,
people in our (american) culture are raised to bow to the
scale. Particularly women. My sister in law is overweight (her
definition). I ask her if she would care what she weighed if
she had a 21" waist. Of course not. However, she contiues to
use the scale as a sign of progress.

-D. Israel

[Suzee]

> Problem is, some people (read: the insurance companies) are
> stuck on the numbers. They don't care what it looks like,
> they only care about the number on the paper. (It's probably
> some fat guy in Connecticut making the decision...) Not only
> that, people in our (american) culture are raised to bow to
> the scale. Particularly women. My sister in law is
> overweight (her definition). I ask her if she would care
> what she weighed if she had a 21" waist. Of course not.
> However, she contiues to use the scale as a sign of
> progress.

I look at mine for general purposes, though my waistband is a
better indicator. Thanks to my new job, I may gain muscle and
hopefully lose some of the blubber.

sue

[Wuzzy]

end user <paul@not_real.edu> wrote in message
news:<slrnanv7pp.gq.paul@crane.li-po.edu>...
> There is a book called "Total Nutrition" that is comprised
> of writings by various doctors and a way to measure for bone
> size is the width of the elbow bone(?) when the arm is bent
> at right angles with the elbow forming the angle. Have no
> idea how accurate this way of finding one's bone size is but
> it does help me feel better about my BMI of 29 :_).

Cool, this is true, actually elbow breadth is the main measure
used of "frame size", a measure of skeletal component of
bmi?.. There is alot of good data on the subject of
composition - this is an especially interesting topic in
nutrition for instance the major surveys have taken *temporal*
data (several years apart) on serum and nutrition as well as
anthropometry in large samples hence it is possible to find
temporal relations.similarly lots of data waiting to get
analysed on temporality of serum values, quite exciting -
since it allows *some* generalization on causation. Likely
there is reciprocation happening but there is probably some
net causation. alot of it can be predicted or at least
varified from current literature.. very exciting stuff to look
out for, i think in future.. pah, my opinion..

[Daniel Isr]

"suzee" <suzeeq@nidlink.com> wrote in message
news:3D813391.1FAF@nidlink.com...
> > Problem is, some people (read: the insurance companies)
> > are stuck on the numbers. They don't care what it looks
> > like, they only care about the number on the paper. (It's
> > probably some fat guy in Connecticut making
the
> > decision...) Not only that, people in our (american)
> > culture are raised
to
> > bow to the scale. Particularly women. My sister in law is
> > overweight
(her
> > definition). I ask her if she would care what she weighed
> > if she had a
21"
> > waist. Of course not. However, she contiues to use the
> > scale as a sign
of
> > progress.
>
> I look at mine for general purposes, though my waistband is
> a better indicator. Thanks to my new job, I may gain muscle
> and hopefully lose some of the blubber.

The waistband is the best indicator! Best of luck!

-D. Israel