Weight and Resistance Training - Measuring body fat %

View Full Version : Measuring body fat %

05-14-2008, 05:10 PM
I've been thinking a lot lately about measuring body fat %, especially as my next goal is to get to about 12% body fat....we'll see. My personal trainer uses 9 point calipers. What do you guys think about pros/cons/accuracy of different methods of measuring body fat %?

05-14-2008, 05:30 PM
I've heard that a dunk tank is the most accurate, but most of us don't have access to one. Short of that, I think that nine-site calipers consistently done by the same experienced (emphasis on experienced) person is the most accurate. Next best would be a three- or four-site caliper test, but why not go for all nine sites?

I'd say that bioelectrical impedance is next best, both handheld like the Omron and Tanita-type scales. They vary a lot during the day and depend on hydration. They also can give you different numbers depending on where you carry your fat. If you're bottom heavy, a Tanita scales will read high on you because it's sending its electrical current through your lower body, where a disproportionate amount of your fat is stored. Also, the algorithm they use is based on age and Mel and I can tell you that it reads BF very differently for someone who's 33 than someone who's 53. In fact, if I set my scale for 20 years younger, it's much more in line with a nine-site caliper reading. Does that mean I'm really 20 years younger?? :lol: They're good for tracking trends over time, but not real accurate for many people.

In my experience, the online sites that take your measurements and supposedly determine your body fat from them are pretty worthless. There really isn't any way to determine your body composition from your measurements. The tape measure can't tell if it's on top of fat or muscle.

One important thing to note is that no method is very reliable for someone who is obese. It's very difficult to caliper someone who is obese (though they are developing extra-wide calipers) and bioelectric impedance isn't very accurate either. I've read that someone needs to be in the high 30s to start getting accurate readings.

I think you can be pretty confident about the accuracy of your nine-site readings, Midwife. :)

05-15-2008, 12:22 PM
I think DEXA (dual energy X-ray absorbtiometry) is the most accurate method, but it isn't widely available. You might see if a University hospital near you does DEXA BF measurements, for a reasonable fee. They might even have a free study you can join. Here at Columbia they were giving free three month gym memberships as well as body composition analysis if you joined one of their studies. Unfortunately I didn't qualify, as i was already working out.

I am not sure how important it is to track BF%, since the tape measure, scale and mirror do a pretty good job telling us how close we are to our goal weight.

05-15-2008, 12:28 PM
I've been thinking a lot lately about measuring body fat %, especially as my next goal is to get to about 12% body fat.

If you hit 12% BF at 5'9" 164#, you will be ready for the Ms. Olympia.

05-15-2008, 06:32 PM
f you hit 12% BF at 5'9" 164#, you will be ready for the Ms. Olympia.

lol, no kidding! But most female competitors are on stage at about 8% which is not maintainable, or healthy.

Why do you want to be at 12%? For most people, that is a really unmaintainable bf%. At 12%, you will see some muscle striation, prominent veins in your shoulders, groin area, your bicep vein, and perhaps the veins in your abs. Why do you want to be that low unless you are heading for a figure, fitness or bodybuilding competition?

05-15-2008, 08:26 PM
Thanks for the info, guys!

Why 12%? I was asking my PT about a new goal and that is one that she mentioned. A problem I have right now is that I have no specific goal---and I like specific goals. I've dropped 4% body fat each month for 3 months. I know it won't always be that easy as the percentages get lower. Right now I am at about 16% and I just don't really know where I'll end up.

Except that I do know there is no real "ending up". I will always be a work in process. I'm trying to focus on behaviors and let my body just kind of do what it will as a side effect of those behaviors.

And I need to change my stats. I always thought I was 5'9" but I measured myself and I am 5'8"..... :)