Body Fat at the Y

JenAndSome

I had a fitness assessment done at the YMCA today which I had never done anything like that before. Everything I have done so far the past couple years has been on my own. Part of the assessment was getting weighed on the Tanita BF-350 which takes your age and height into consideration, sends some sort of something through your body to test the resistance and spits out a number that is supposed to be your body fat percentage. The number it gave me was 12.9%. Obviously that is pretty low for a woman and I was thinking it would be more like 20-22% or higher. I have looked online and have only found one review which was a positive one for this one. Does anyone have any insight as to how accurate these things can be? I only ask because I have been trying to keep up with my protein and I feel like I eat a lot of it already and can still barely keep it high enough to donate plasma twice a week. Well, that and numbers are fun.

dixiewhiskey

I haven't used one before but I would take it with a grain of salt. Scale BF% tends to be inaccurate from what I've heard.

I usually just take my measurements and go by the US Navy calculator for BF%.

What does your BF% say according to this calculator (near the bottom on the right hand side)? http://dudeswithmoobs.blogspot.ca/p/using-us-navy-body-fat-calculator.html

There used to be a better one but it's not online anymore. I'm curious how close you are to the 13% you got from the scale.

JenAndSome

That calculator gives me a much more realistic 20%.

lamps1303

I am always sceptical about scales/machines that measure BF%. Depending which type you use, it won't take certain parts into account. The scales (from what I hear) basically ignore the upper body, particularly the arms. If you use one where you hold the handles, it will ignore your legs. Best way to assess BF is with a Dexa scan, but they are very pricey. Calipers are the easiest and most cost effective way. Try to limit margin of error where possible but they are useful for getting a rough figure. You could also take measurements and input them into an online calculator. Although there are risks of inconsistency in terms of measuring from the same place each time.

pyrowill

12.9% sounds unrealistically lowwwww. Hope it didn't cost too much!

JenAndSome

I didn't figure it would be very precise. I was mostly wondering if others had used this machine or something similar and what sort of numbers it gave them vs other body fat measurement methods. Thankfully, the whole fitness test was free as I am a fairly new member at the Y.

DWBalboa

I don’t know much about the system you mentioned but I do have a little understanding of the science behind it. The problem with using your bodies resistance is that it can vary day to day or even within a few hours depending on a multitude of variables such as moist or dry skin, rather or not you may be sick or well. It also depends on where the measurements are taken, finger to finger, hand to hand, and so on; the more body involved the more resistance. I could give you the equations used to make calculations but I fear I may have already bored anyone who’s actually read this far.
I would go with the old fashion proven method of using calipers (still not 100%), but then again I’m an old school kinda guy. I’ve never done the dunk tank test but that is from my understanding the most accurate method.
The Navy standard that the person above mention is a decent baseline to use. Either way, whatever method you use, don’t fret too much about the results. What’s important is how you feel in your clothes and how you feel about yourself.
V/r,
DW

DWBalboa

Oh thats a "y"...not a "v".....thought this thread would be more entertaining

Well “at the Y” does have a little innuendo that would lead others here too.

Mrsbeale11

Oh thats a "y"...not a "v".....thought this thread would be more entertaining

lol!

DWBalboa

I don’t know much about the system you mentioned but I do have a little understanding of the science behind it. The problem with using your bodies resistance is that it can vary day to day or even within a few hours depending on a multitude of variables such as moist or dry skin, rather or not you may be sick or well. It also depends on where the measurements are taken, finger to finger, hand to hand, and so on; the more body involved the more resistance. I could give you the equations used to make calculations but I fear I may have already bored anyone who’s actually read this far.
I would go with the old fashion proven method of using calipers (still not 100%), but then again I’m an old school kinda guy. I’ve never done the dunk tank test but that is from my understanding the most accurate method.
The Navy standard that the person above mention is a decent baseline to use. Either way, whatever method you use, don’t fret too much about the results. What’s important is how you feel in your clothes and how you feel about yourself.
V/r,
DW

So the topic caught my curiosity and I thought I’d do a quick research on our old friend the internet and the first page was an article in Shape magazine. It’s a fast read and I though informative. So for your reading pleasure I give you:

http://www.shape.com/weight-loss/weight-loss-strategies/best-and-worst-ways-measure-body-fat

erickirb

They are typically quite a bit off, good for tracking progress but not for the exact number. I had one done a few years ago, I figured I was in the 9-10%, and it told me I was 6.3%, and I wasn't ripped to shreds, so quite a bit off.

Azdak

The model used for your assessment is a pretty decent one. We use the BC 410, which is the top Tanita scale, but we also have a 310 in a closet somewhere.

I was always a skeptic of bioimpedance myself, but I have found that these Tanita models do a decent job of estimating body fat.

That being said, I have occasionally had some numbers that made no sense at all. In fact I had a situation similar to yours just last week--a guy who was easily 22%-24% came in at 13%. Sometimes there can be issues between using the "standard" and "athlete" settings. Certainly if you work out before the test, it will significantly skew the numbers.

I still don't have a definitive explanation for the outlier numbers. In general, after using the Tanita scale for about 500 tests, I have found it to be acceptable in terms of accuracy. But I have had maybe a half dozen of instances where I get really wacky readings for no reason.

The person who did the test should have recognized this and either arranged for a repeat measure on another day, or told you that the number was meaningless. In any case, while the numbers for this scale are usually reasonably accurate, in this case it absolutely was not. You should try a retest on another day.