Addicted to crappy piece of plastic that measures % body fat comp??

Can't tell you what's wrong with you but I can tell you that the hand held thing is pretty senstive.  Depending on when you ate last or how hydrated you are can mess with the results.  So, go by your pants, not your BF%.  Calipers, while accurate, are only as accurate as the person using them.  Lots of room for human error. Next time you do your BF with calipers, read the instructions for the hand held thing and make sure you do what they say.  Then you might actually be able to make a fair compairson.

Is the thing at your office a DEXA reader? (from exercise.com):

DEXA (dual energy X-ray absorptiometry)

This test is used to measure bone density, but it also measures body fat percentage as well as where most of your fat is (as if you didn't know). The facts about DEXA:

* DEXA uses a whole body scanner and two different low-dose x-rays to read bone mass and soft tissue mass.
* It takes about 10-20 minutes to do a body scan
* It provides a high degree of precision with a 2-3 % margin of error.
* This is considered a gold standard for measuring body fat and bone density
* It's painless


Calipers can be very wrong depending on who's doing the reading, and even 2 different calipers can register very different readings. Something I do to get a better guess when measuring is to take 3 or 4 readings at the same time, and then average them out. And yeah, you'll get different readings based on how hydrated you are, when you last ate, etc. I try to take my measurements right when I get out of bed in the morning.

There is a 12 point test you can take that will give you a more accurate reading, but it requires more of a manual calculation and more manual calipers. If you are really worried/curious about your BF, the most accurate way to measure is called hydrastatic testing (underwater weighing). This is from Exercise.com as well, and describes how the test is done:

* You sit on a scale inside a tank of water and blow out as much air as you can
* You are dunked underwater, where you blow out even more air
* Since fat is lighter than water, the more fat you have, the more you'll float. The scale measures underwater weight to figure out body density.
* The margin of error is around 2-3%, but the accuracy depends on the amount of air you expel. You have to blow it ALL out or it won't be as accurate.
* This is a difficult way to measure body fat since it can be uncomfortable and even scary to be dunked underwater with no air in the old lungs.

This is a pretty expensive way to get tested too, around $50 - $100 a pop.

All in all though, the best way to judge is to look in the mirror, and your clothes are the most accurate way. It sounds like you are doing very well, and I wouldn't worry too much about what some pile of plastic tells you...


Edited by emartin10 2005-09-16 11:40 AM

No- I don't think that's what that plastic piece of crap is.  It only takes a few seconds to give you a reading.  All you do is hold your arms out straight in front of you while gripping the handles on this thing.  Does anyone know what I'm talking about?  Surely I'm not crazy!  Whatever it is, I'm addicting to getting in accurate readings from that thing!

O.k. I have to chime in. I have seen and used almost all forms of body fat analysis equipment at one time or another and do have an opinion.

Other than autopsy which really isn't a viable option for living people, there is not a perfect method for determining body fat %.

The best method is hydrostatic weighing. This is where they weigh you underwater. The problems with this method include: 1. Very few places offer it. 2. You have to exhale all your air while under water (this tends to make people nervous). If you don't exhale all your air you will have added bouyency. 3. You have to sit very still as any movements can affect the readings on the scale.

Next is probably Skin Calipers. Problems: 1. 7 Site skinfolds are the best, but most gyms and other places will only do 4 or 3 sites. 2. Accuracy is dependent on experience of the person performing the test. Even 2 or 3 millimeters up or down on a site can make a diference as you are measuring milimeters!!!! 3. If the same person doesn't redo the test, you will lose the consistency of the same person performing the test.

Bioelectrical Impedence: Problems: 1. Cell hydration varies by the minute (Especially in Women). 2. Consistency between machines is very questionable. 3. Calculations are really blackbox as diferent methods exist for determining bf%. 4. Height or distance traveled for the electric current can play a role. This is probably my least favorite method.

So as you can see all the methods have issues. It should be noted that the only accurate thing you can do is utilize the same method repeatidly to recognize a change in BF%. Just as you should use the same scale at the same time if you are looking to track weightloss changes, you should use the same method at the same time (of the month and day, for men and women) to track changes in bodyfat percentage.

Just an opinion from someone who worked in the fitness/Physical Therapy industry for 10+ years.

Don't forget the bod pod. It's like hydrostatic weighing, except with air.

the little hand thing is not that accurate despite what the nurse says.  DEXA is supposed to be as accurate as the body dunking in a tank of water which is usua;;y the gold standard.  You have to find a scanner that has the software to support the test.

Janelle-

Screw the bf%. I have spent over thre months not losing a pound. I've had to tighten my belt past the last hole by almost 3 " (I'm cheap and punch new holes). I'm wearing jeans that I couldn't get my rear end into a year ago. Am I better off - YOu betcha! Don't worship at the altar of numbers.

Enjoy the positives - this is coming form an old man.

this post is very close to being 100% accurate. I've had a number of DEXA scans done. it is known for measuring change very accuratley, and is pretty good at measuring actual percentages. But still not great.

HD

Janelle,

There's a similar pile of crap in the gym at my office. Yes, its crap and probably not very accurate. If you look in the mirror and think, "damn, I'm hot" (which you ought to judging by your Hotties O Month pics) then all's well.

Oh, and holding piles of crap makes your hands stink!

Tom

two things:  Tom:  LOLOLOLOL.  literally.

and i agree.  janelle, you have the cutest (low fat %) smile on BT. screw the body fat % and go with your clothes and the mirror.