# Darryl Roberts Attacks Body Mass Index in New Documentary



## Curt James (Oct 29, 2011)

YouTube Video










Filmmaker Darryl Roberts on his documentary *'America the Beautiful 2:  The Thin Commandments.'* The film looks at body image in America and how  certain industries profit from it. (Oct. 28)





YouTube Video










A new documentary by Darryl Roberts that explores why we have an  unhealthy obsession with dieting in America and who benefits from  selling us the thin is healthy ideal.

And his previous film:





YouTube Video















YouTube Video


----------



## mp340 (Oct 30, 2011)

interesting stuff man


----------



## Kenny Croxdale (Oct 30, 2011)

r





Curt James said:


> YouTube Video
> 
> 
> 
> ...



*Body Mass Index*

It has never made sense.  As Roberts notes, it is a joke.   

However, the other method aren't much better. 

*Bioelectrical Impedance Scales and Devices*

These devices are no better.  They are incredibly inaccurate.  

There is a protocol you must follow with BIA devices

*BIA Site Sensitive.* 

Scales that you step on measure more of you lower body fat percentage. 

Thus, if you store a lot of fat in your lower body, BIA Scales will show you fatter than you really are.  

If you store less fat in you lower body than upper body, BIA Scales will show you less fat than you really are.  

*Hand Held Omran Body Fat Monitor*

The same is true with hand held devices such as Omron.  

*Body Fat Calipers*

Even this method is flawed.  At best it is an estimate.  

A large part of the problems is untrained individuals who purchase a cheap pair and then take their measurements or a friends.  

Another problem is that the caliper measurement method is based on hydrostatic weighing, which is guessing at best. 

*Hydrostatic Weighing*

Even this "Gold Standard" is flawed. 

*Fat Floats*

Throw some butter in the tolit and you will see what I mean.  

One of the determinate factors in calculting your body fat percentage with this method is bouyancy.  

*Lungs*

The amount of air you have in you lungs determines how much you float, as well as body fat.  

*Residual Lung Capacity*

Prior to hydrostatic weighing, your residual lung capacity needs to be measured.  Doing so, allow them to provide a more accurate "guess" of your body fat percentage.  

*Lungs and Air*

Again, the reason for measuring residual lung capacity is that air retain in the lungs makes you float more...as does fat.

Thus, by measuring the amount of air you retain in your lungs allow for a more accurate in hydrostatic weighing. 

*Underwater Scale*

Hydrostatic weighing involves sitting on some scales.  You then blow all the air out of you lungs. Then you sit there underwater and wait for the scale to become steady. 

*That AIN'T Normal*

That is one of the hardest thing for anyone to do (been there/done that).  Blowing all of the air out on the residual lung measurement device and then doing it underwater are completely different. 

Very few can blow out as much underwater.  It's NOT normal.  

That means some of the hydrostatic weighing measurement is compromised.  

*NO Measurement = NO Good*

Any hydrostatic weighing performed without measuring residual lung capacity is worthless.  

*Ethnic Group*

Anther factor that compounds the problem, is there are different formulas dependent on your ethnic group.  

*Estimation of Body Fat Percentage*

No matter what type of reading you take, there is a plus/minus factor.  That means you body fat percentage could be higher or lower.  

*Mirror Measurent*

Strip down in front of a mirror.  If you look fat, you are fat. 

As one semi bodybuilder told me, "The mirror doesn't lie." 

*Tape Measure or Clothes*

For most guys, an increase in the waist means your adding more body fat.  

For many women, if your ass and/or thighs won't fit into your pants or you pants look like a stuffed sausage...your body fat has probably increased.

Kenny Croxdale


----------



## Built (Oct 30, 2011)

DEXA. Next to post-mortem dissection, it's the gold standard for body composition.


----------



## Curt James (Oct 30, 2011)

Kenny Croxdale said:


> *Ethnic Group*
> 
> Anther factor that compounds the problem, is there are different formulas dependent on your ethnic group.



Why or what specifically?


----------



## Kenny Croxdale (Oct 31, 2011)

Curt James said:


> Why or what specifically?



Hi Curt,

This article provides some insite. 

http://new-fitness.com/body_fat_analyzing.html

*Hydrostatic Weighing*

"...athletes tend to have denser bones and muscles than non-athletes, which may lead to an underestimation of body fat percentage. While the body fat of elderly patients suffering from osteoporosis may be overestimated. To date, specific equations have not been developed to accommodate these different population groups."

*Calipers*

"Different prediction equations are needed for children and specific ethnic groups (over 3,500 equations have been validated). This approach usually uses underwater weighing as a reference method."

*Built*

As she notes, dissection is the best method.  DEXA has received favorable ratings.  

However, I question how accurate DEXA really is.  

Kenny Croxdale


----------



## TooOld (Oct 31, 2011)

I hate BMI. My Doc disagrees with it but still has to use it.


----------



## patricio (Oct 31, 2011)

BMI was conceived as a parameter to predict mortality related to excess weight. It works perfectly for that purpose, as long  as you don't apply it to very athletic or muscular patients, or  children.


----------



## Built (Oct 31, 2011)

DEXA projects a 3-D body onto a 2-D image, and then works out the math. The margin of error is thus compounded by this flawed, but useful model. 

A better estimate would come from the use of a C-T or MRI image; the cost however would be prohibitive with very little return in terms of accuracy. Of the currently available, practical methods, DEXA is the way to go.


----------



## Curt James (Oct 31, 2011)

Kenny Croxdale said:


> Hi Curt,
> 
> This article provides some insite.
> 
> Body Fat Analyzing - Comparing Methods for Measuring Body Fat



That article offers *no *reasons at all _why _there are different formulas used depending on a person's ethnic group.


----------



## Merkaba (Nov 1, 2011)

Curt James said:


> That article offers *no *reasons at all _why _there are different formulas used depending on a person's ethnic group.



Most ethnic group studies are always bullshit and can be traced by to cultural differences, not ethnic.


----------



## Kenny Croxdale (Nov 2, 2011)

Curt James said:


> That article offers *no *reasons at all _why _there are different formulas used depending on a person's ethnic group.



*Bone Density Readings*

One of the reasons, as noted below, is the difference in bone density.  The article references women; however, that appears to be true for men, as well.  

*Skin folds are also hard to obtain in the very obese or very skinny persons.*

"_ASSUMPTION errors_ ??? most equations that attempt to predict body fat from skin folds used underwater weighing (UWW) as the reference (criterion) method. UWW assumes that the fat free body has a constant density of 1.100 g/cm 3.  However, _black and Hispanic women have a higher density of 1.106 and 1.105 respectively due to higher bone mineral content (other ethnic groups also have various densities other than 1.1)."_

*One Size Doesn't Fit All*

Thus, to obtain the most accurate reading (which isnt' that accurte), you need to utilize the right equation for the right ethenic group.   

*Plus Minor Factor*

Another problem is "Most equations are accurate in the range of 4-5% and the actual reading can be plus or minus 10% of your real fat ."

*Ball Park Reading*

A 4-5% variation is  huge.  That means a 200 lb man would have either 8 pound more fat or 8 pound more muscle (based on a 4% of the plus or minus factor). 

A 4-5% difference give you a ball park figure.  

A 10% plus or minus factor give you a galactic body fat percentage rating.  

*Right Tool For The Right Job*

Each equation favors a different demographic group.  Thus, you need to pick the right one for the right group.

*Another Example:*

"Note: Jackson Pollock formulas best for very lean people. Not recommended for men above 12% and women above 14% body fat."

*Body Fat Measurements *

The take away message is that "ball park" body fat reading is the best you can obtain.  

*Exception To The Rule*

As Built stated, dissection give you a "dead" on reading.   

Kenny Croxdale


----------



## Tomn (Nov 2, 2011)

interesting stuff..


----------

