Body Fat
OK, so I go to my gym, weigh myself (204, and I can see abs), and have the guy check my body fat. He uses one of those hand held dealios. It registers 18%!! Now, a month or so ago, one of the other guys tells me that the thing can be off by as much as 5%! So I figure, fine, by this point in the day I’ve taken in a lot of liquid, but I don’t really know how much of that figures in. I discuss this with gym-dude runnin’ the machine. He says, "Well let me try something". He pushes a couple buttons and we try again. This time it gives a error message "E4". We repeat it. Same result. He says the device is usually set for the general populace, but has a "athlete" setting, which is what gave us the E4 reading. He tells me that only happens if the Body Fat % is below 6%. Now I’m really confused. But if I take the 5% error margin, I’m guessing myself between 11% and 13%. But it’s only a guess.
To confuse it more, I repeated the process a few days later, at only 200 lbs, (yep, a 4 pound fluctuation, and that’s fairly normal, depending on time of day and fluid intake) and got the exact same body fat reading.
I see a lot of people on here post their body fat percentages and progress, and I wonder how they get accurate results, or it they really are accurate. I mean, submersion testing, reputably is the only reliably accurate method. Calipers can be, if you use them early in the A.M. before fluid intake, but water weight, pinch tension, math calcutlations, all that can skew the result. And I think I’ve demonstrated the lack of reliability of the hand held dealio’s. So how do we REALLY know?
Gym dude finally told me that basically, the only thing to really go by is if there’s a change. The number itself may not be correct, but it will let you register change from measurement to measurement. I pulled up my shirt, flexed my abs, and said, "That’s not 18% fat" as I flexed my abs in his general direction!
So, how do you know? How can you trust the number? What are others out there using to get their percentages? I’d like to know?
July 1, 2007 at 5:15 pm
My first choice to measure the bodyfat is the mirror, but if I want a number, I’ll use calipers (old fashioned, not digital).
I know they won’t give an accurate reading like the dunk test, but it’ll do in a pinch (D’oh! bad pun!) and give me a general idea of where I stand bodyfat wise.
After taking my readings, I punch my numbers in on a website that calculates my bodyfat based upon the various methods available (jacson/pollock; Durin-Womersley; etc.etc.)
All the different methods produce different results (my last reading ranged from 6%-11%). I pick the one that feels right, which is usually the highest percentage.
July 1, 2007 at 5:18 pm
I use an OMRON handheld BF Analyzer. My buddies and I did our own little "Unofficial" test on it. 5 of them went together and had a bodyfat "Dunk" test (Our gym sponsors one every couple of months). Right after getting their BF done by the "Pro’s" we used the Omron analyzer on them. It was accurate within 3% of 4 of them. One of them read "Error" but the dunk test said he was at 5% (wirey little dude). The trick I’ve found is consistency. The manual states to use the Athlete setting if you exercise regularly. Following that rule, I measure my bodyfat first thing in the morning, immediately after weighing myself, before eating or drinking anything. Even if it is off by a few percentage points, by being consistent I am relatively confident I’m getting an accurate trend one direction or the other each week. Hope this helps - I’m sure there are others that will chime in with other good information and experiences.