July 22, 2015
DEXA Versus Calipers for Body Fat Estimation
This is going to be another fairly short piece since I’m still entrenched in editing the book and can’t think of anything much more useful to write about at the moment. In it, I want to look at some issues/comments/etc. that have come up regarding body fat percentages (BF%) and estimates.
There is a common occurrence online (my support forum has an entire thread) for people to ask for visual estimates on BF%. No, it’s not a perfect method but folks who have done this for a while can give at least a ballpark estimate. You can also find some neato graphics people have put together for men and women online.
Now, for a lot of years, methods such as calipers, bioelectrical impedance (BIA, crap IMO), underwater weighing, etc. were used to estimate BF% and I wrote a long series about body composition, numbers, problems, recommendations, etc. James Krieger also did a really good series on the topic.
Now first realize that all body fat estimates are only estimates, which are only estimates. The only truly accurate method to get body fat percentage is to dissect someone and measure it out and you can’t do that very often (it’s also messy). All BF% estimates have some built-in assumptions and some amount of error so it’s always just an estimate.
But here’s where the recent problem has come in.
DEXA versus Calipers, etc.
One of the more recent approaches to measuring body composition is DEXA (Dual-Energy X-ray Absorbitometry) which does a full-body scan and can measure things like bone density (critical for women) and other tissues. And it gives what is proposed to be a more accurate estimate of BF% than older methods. It can even do something where it gives you one value for upper body and one for lower body. I suppose folks could use this to look at regional changes in BF% but I think whole body BF% is more valuable.