Re: You Think You Know What Your BF% is ?

[Guest guest]

I don't lose much sleep over my %BF but wish I had more muscle.The tell that the cheat is in on all those electronic toys is when they have you enter height, age, activity level, etc...  glorified look up chart, indexed to one variable bioimpedance.The bioimpedance measure might be a little more accurate with more contact points. I thought of adding a hand grip to my tanita, so one electrode would touche both feet pads, and the other both hands. It seems the tanita is biased to measure leg conduction, while hand held will see arms and trunk but probably be dominated by arms. Then I'd have to re-calibrate but if it was more consistent that would be betterWhatever... full body scans for everybody and free health care for all ..  it's only money.JROn Jul 30, 2007, at 6:49 PM, Rodney wrote:Hi folks:A newly-opened local drug store is running sessions offering sort-of-useful free services to try to drum up business. These include a total cholesterol test, an ultrasound heel bone 'density' scan, and a BF% measurement, among others.The latter two are of interest to me, although I also had the cholesterol test done, which came out about where I had expected. I turned up for the BF% event recently, just agog waiting to see what the number would be.Soon after I arrived and was discussing general health issues with the RN who adminsters the test, I said that I wanted to drop my weight another five pounds to get to a BMI of 20·6. She replied: "You're slim, you certainly don't want to lose any more weight." I explained that I had my reasons and she proceded with the test. It was done with a hand-held bioelectrical impedence gadget which has two handles. The patient holds one handle of the gadget in each hand, thumbs up, with arms extended out in front, horizontally, level with the shoulders. After entering some data in the gadget, which I believe included age, height and weight, the digital readout came up with the number. Ta daaaaaa: BF% = 20·4 !!! "You don't LOOK like a body fat of 20·4%", she said. A few months ago the US Navy calculation had been saying my body fat was 14%. So after returning home from the drug store, I decided to do a Google search and calculate my BF% using all the methods available at the sites Google listed.The readings came in at anywhere between 9·7% and 23·7%. Here is a listing of the methods used and what they came out at most recently:US Navy: 17·5%-Pollock 3-circumference: 11.1%Biofitness.com: 23·7%Bio-impedence at drug store: 20·5%mac.com:Simple method: 9·7%Four skinfolds: 18·6%Csgnetwork.com - three circumferences: 20·5%Lowcarbdiets.about.com:A) 15·5% 14·1%Healthcentral.com: 15·3%Bmi-calculation.net: 18·14%NOTESAs for the US Navy method, I notice huge variations in my neck measurement, measured exactly the same way, from week to week. Lately I have put on about four pounds of weight according to the scale, and my abdomen circumference has increased, yet my neck measurement has *dropped* from 15" to 14 1/4" !!! That change alone makes about 1.5% difference to my US Navy BF% result.A couple of the sites referenced by Google used skinfold measurements. Recently a report was posted (author Dr. Jimmy Bell) at to the effect that different people accumulate body fat in different places. Some people, according to this report, have much more visceral fat than others. I have since had that information confirmed by a radiologist I know, who says he sees this variation in full body CT scans. So it seems that this large variation in visceral fat among different individuals renders skinfold methods unreliable, since they are presumably unable to take account of the extent of visceral fat?How does a bioelectric impedence device measure visceral fat when it is held in both hands, with the electric current presumably running up one arm, across the body just below the neck, and down the other arm? Or fat any place, for that matter, except where the current flows? It seems to me all these methods rely on an assumption that fat in one specific location - the one measured - accurately reflects the amount of fat buildup everywhere. If Dr. Jimmy Bell is right, that assumption is wrong! In their introductory write-ups, most of the above sources claim their method is "highly accurate". I suspect that none of them are reliable. For that matter is immersion reliable?Clearly this matters for people on CRON. If my body fat is really less than 10% then I have already exceeded my target and am beginning to approach the 'DANGER - do not go below' level. But if it is over 20% then I would have to lose another ~thirty pounds to get down to my tentative target of 10%.So how confident are *you* that you know what your BF% is? I am very confident that I do not know what mine is. Sigh.Rodney.

[Guest guest]

Rodney,

The " gold standard " for BF% is the underwater

weighing, where the techs find out your volume of

displacement in a tank of water. Most colleges and

universities with a kinesiolgy department can do this

for you at a reasonable cost. Our local state U. does

it for $25.

Share your M & Ms. There are bags and bags of them all over the place. If you give

them one of yours, even one of the green ones, you will not be lacking. Honust

Injun. Now apply this to Time, Concern, Touch, Interest and Being Vulnerable.

Hugh Elliott, Standing Room Only weblog, 02-14-03

________________________________________________________________________________\

____

Got a little couch potato?

Check out fun summer activities for kids.

http://search./search?fr=oni_on_mail & p=summer+activities+for+kids & cs=bz