Thread: Darryl Roberts Attacks Body Mass Index in New Documentary

interesting stuff man

r

Originally Posted by Curt James

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)

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:

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

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

Originally Posted by Kenny Croxdale

Ethnic Group

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

Why or what specifically?

Originally Posted by Curt James

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

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

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.

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.

Originally Posted by Kenny Croxdale

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.

Originally Posted by Curt James

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.

Originally Posted by Curt James

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