Body Composition Analysis - what are the options?

I'd really like to have my body composition done... but I'm not sure what all the options are... along with the pros and cons of each.  What would you all recommend??

I'd like to know my body fat (true, not pseudo-estimated), BMR, RMR, etc.

The Gold Standard for years has been hydrostatic body fat testing, which is done through submersion in water. New techniques are Dexa Scan (expensive) and Bod Pod testing.

I have had my body fat tested twice through hydrostatic weighing. I haven't had body fat tested through the other measures. My BMR and RMR seems high to me, so once again, take the results with a skeptical eye. Formerly obese people tend to burn about 15-20 % less calories during exercise and rest, than people who have never been obese. It can give you a ballpark figure, but you will have to adjust the amount to your own needs and activity level. The caloric range that I was given, is on the high end to what the dietitian recommended to me, although the body fat testing recommended more calories.

gail

Gail, would you let me know the next time you go get tested please? Thanks!

I would highly recommend either a DEXA scan (which can be very expensive.  I  only paid $50 for mine last Oct at COSI in Ohio) or a Bodpod (which is usually inexpensive.  I paid $25 in Feb).  Google both the get the full "rundown."  Best of luck to you!

Jennifer

I had mine done in a Bodpod. I think it was accurate, but not as accurate as hydrostatic. It was cheap, though. I think I paid $30 in Vacaville, CA.

Was that at Gold's in Vacaville? I'm in Benicia.


Gail

Yes.  Took about 20 mins with the explaination, testing, and then BMR is calculated manually by the trainer.  They give you a printout with the results.

Probably the easiest to find is an electrical resistance test. Exercise physiologists use fairly sophisticated ones that you stand on and hold on to grips at the same time. They measure not only total fat but fat in various parts of your body (arms, legs, etc). Bod-Pod's are also fairly common now. Hydrostatic or DEXA scan testing are probably a bit more accurate.

In terms of RMR testing, there's a test where you breathe through a tube for 10 minutes after fasting and abstaining for caffeine for 4 hours. It measures oxygen usage, and then calculates the expenditure of energy based on your height, weight, gender, and age. The tests are supposed to be accurate within 2% which is 40-50 calories a day, either way, when the tests are adminsitered properly.

My testing seemed pretty accurate. I'm going to have it redone in September.

I've done everything but DEXA. 

The only way to know your true body fat is via an autopsy. Every method, even DEXA, has some estimating built in. DEXA is the Gold Standard because it uses 3 levels of measurement. Everything else uses two. If you can get insurance to pay for your DEXA scan, that's the best.

Second best is hydrostatic weighing (dunk test). It can be off by as much as 3% on average (though in individuals it was off by more) but it tends to do a good job of being consistant. So you can use it to measure trends most of the time. It can be thrown off if you aren't good at getting the air out of your lungs.

Then we get the BodPod. It's touted as just as accurate as hydrostatic weighing without having to get wet but that was not my experience. (And studies show it's slightly less acurrate on average.) It can be thrown off by having air in your swim suit. And it's not as good at being consistant so it's harder to know if you truly are changing (and in the right direction).

Next we have calipers and bio-impedience. Calipers are all over the place. A good measurer can be extremely accurate with them. But a bad one is just giving you a random number. Bio-impedience, IMO, can get you in the ballpark but it varies from day to day by as much as 5%! It can be thrown off by all sorts of things including how hydrated you are. I have one of the fancy scales where you don't just get eletricity shot through your feet but also there are hand-grippers and I don't think it's particularly accurate even then.

Here's an example of what we mean by estimating....  if I tell my scale I'm a women, it says my body fat is 27%. If I say I'm a man, it says it's 18%. When my scale was telling me my body fat was 15% (and it was actually closer to 18%), the hand-held bio-impedience devices were telling me it was 27%!

If you want to read more, start with this article and work your way through the entire series. It's very interesting:

http://weightology.net/weightologyweekly/?page_id=146

I had mine done for $35 at a Sports-Science Clinic but I don't know how accurate it is. It used the bioimpedance method, I stood on a machine with bare feet and held onto handles to get the measurement. It was quick, pain-free and gave me a printout of my weight broken down by fat, muscle, water and also went so far as to put the percentages for left arm vs. right arm, (same for legs, torso, etc.) It gave me a ballpark idea of where I'm at.