Question about calculating Body Fat %

CoryIda · February 2011

According to my scale at home (which is new but not a very fancy or expensive scale), my Body Fat % is several points higher than what my Body Fat % is based on my measurements... which do you think is more accurate?
My waist to hip ratio is in the healthy range, so it seems like the lower number would be closer to correct, but I'm not sure. What do you think?
I can’t afford an expensive test and, from what I’ve read (I like learning stuff), calipers aren’t all that reliable either because most people don’t know how to use them correctly.
I’ve read that the measurements are the best way to gauge over all health risk, but I’m not sure if they are all that accurate for gauging Body Fat %...

chuckanderson · February 2011

Probably neither out of those 2 methods.

Get a pair of calipers and ask someone who has used them before to do it.

antipholous · February 2011

The only accurate way to do it is the water method, but you're probably not going to be able to afford or find a place that would do it.

Calipers are the best way after that, but you'll need to find someone who knows what they're doing. The difference between muscle and fat is subtle, and many people count fat as muscle or vise versa.

I'd go off your measurements than a scale, though, if you were picking between those methods.

Monicamarkt · February 2011

Bod Pod is the next reliable after under water weighing. And then DXA, and then the Calipers and then BIA (the scale or hand held). The BIA is within 3-5% and the calipers can be within 3-4% so go by how you feel and your measurements.

CoryIda · February 2011

According to my scale, my Body Fat = is 38% but, according to my measurements, my Body Fat = 31.65%

Most of what I've read says the calipers aren't very reliable (margin of error as much as 7%) because there are so many formulas, different ways people measure, and also they may not pinch enough/pinch too much...

hroush · February 2011

According to my scale, my Body Fat = is 38% but, according to my measurements, my Body Fat = 31.65%

Most of what I've read says the calipers aren't very reliable (margin of error as much as 7%) because there are so many formulas, different ways people measure, and also they may not pinch enough/pinch too much...

I just purchased a caliper online for about $4. Is it top of the line? no, but it will give me a much better idea than measurements (they say I'm at 25% body fat :noway:). Also remember there is power in repetition, do the measurements 3-4 times and you should be able to get a good idea of your true measure.

ciaobella47 · February 2011

I don't trust to the scales to measure body fat %. If your scale has this feature it's, at the very least, a good way to track if your percentage is trending downward or not.

Google BodPod or body composition testing near your area. They are highly accurate and really not that expensive. Here in Salt Lake City, the BodPod cost me $25 (that includes a consultation).

The range of error for this test is ± 1 to 2.7%. (Much lower than scales and measurements.) The university where I did my testing stated that the BodPod is as accurate as hydrostatic weighing, but quicker and easier to perform.

hroush · February 2011

They have a Bod Pod at my undergrad school, which I don't attend any more. If I would've known, I most definitely would have done it!

CricketClover · February 2011

I don't trust what my scale says either. Mine usually says that I am 32% but I think that is too high and one day it said it was 39%! Then the next day it said 36% then back down to 32%, it would probably change what it said from 5 minutes to the next. I am at 143 lbs right now and while I haven't measured in a while I still think that even 32% is too high.

SHBoss1673 · February 2011

neither a bio-electrical impedance scale (like the one you mentioned), or online calculations are going to be very accurate, neither will a caliper be accurate unless in the hands of a trained professional (calipers measure in millimeters and measurements need to be extremely precise with regards to the tool itself and where measuring is done), and taking self measurements with a caliper isn't really going to work either.

there are 3 very accurate methods (well 4 really, but 1 is super expensive): the hydrostatic method (dunk tank), Air displacement (bod pod), and X Ray imagery (DEXA), the fourth being MRI but that's not really something that people use as it's costly and not usually available. These three will give similar margin for error (between .5 and 1.5 percentage points from true) if they are calibrated correctly (usually they are since they are done by trained professionals).

Some versions of Bio-electrical impedance are more accurate than others, but they usually are limited to metabolic labs as these are professional level equipment that require precise electrode placement and someone to administer the test.

For all the home based methods, your margin for error will be anywhere from 5% to 15% off (sometimes higher with impedance as it depends on your hydration levels).

Ask your health professional for locations of these facilities. In the case of the bod pod, you can go to bodpod.com and click on the link on the bottom right to find locations near you (if they are available).

Sweet13_Princess · February 2011

I have a device made by the company Omaron that calculates your body fat percent by sending an electrical pulse through your body. I heard it's more accurate than the calipers.

Shannon

SHBoss1673 · February 2011

I have a device made by the company Omaron that calculates your body fat percent by sending an electrical pulse through your body. I heard it's more accurate than the calipers.

Shannon

see my above post, this is called bio-electrical impedance and it relies on hydration levels.

thelima · February 2011

Pretty much what SHBoss said.

Sweet13_Princess · February 2011

see my above post, this is called bio-electrical impedance and it relies on hydration levels.

Does the bio-electrical impedance become more accurate if you do it the same time each day? My personal trainer used to do this for me, but she really tried to be consistant in regards to the time of day. I do believe it had something to do with ones hydration levels, as you've said.

Shannon

SHBoss1673 · February 2011

see my above post, this is called bio-electrical impedance and it relies on hydration levels.

Does the bio-electrical impedance become more accurate if you do it the same time each day? My personal trainer used to do this for me, but she really tried to be consistant in regards to the time of day. I do believe it had something to do with ones hydration levels, as you've said.

Shannon

probably slightly, but since it's a function of hydration, you'd have to have hydration levels that are essentially identical day in and day out (and unless you want to use hydration strips and pee in a cup every time you use it, and then drink water until you reach the right level, it's not very realistic to use). Plus Body fat % isn't something that is meant to be measured daily, weekly or even monthly, it's more of a once a quarter type thing, as even if you're a superstar at fat loss, you probably won't lose more than a percentage point or two per month, and really, you won't see any real fat loss if you measure it weekly. the margin for error on them is to large for it to accurately represent them. It's like trying to use a bathroom scale to measure grams, even if it can do it, it's not going to be very accurate.

DeeDeeLHF · February 2011

That last comparison (trying to use your scales to measure grams) was the very best I have ever heard!!

Question about calculating Body Fat %

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