KentuckyTuss saidI've heard the only 'accurate' method to measure body fat percentage is by way of an underwater scale. I'm not sure why everybody stresses about this and that percentage, or this and that number.
Well, here's the issue. Unless the fat percentage is calculated by the underwater method, you'll note that you're always asked your age and level of activity. That's because these devices (and/or the programs that come along with them) add a certain amount to the impedence-derived fat % for visceral fat (fat around your organs, but not in the skin).
The trouble with that is that the assumptions are based upon, essentially, actuarial statistics. In other words, suppose you are a ripped-out, toned 55 year old. If you use one of these devices, they will add an amount based upon the averages assumed for visceral fat for "active" 55 year old persons. Since the average 55 year old is "active" if he walks around the block once, you can see the problem.
So I did a little experiement with the scale that I have. The thing measured my fat % as 18%! I recalibrated the thing for a 40 year old, and then a 30 year old, and got 13% and 10% respectively. Bull bleep!!
It's not so much stress...it's wanting a measure that is comparative to other people.
If you are measured underwater, your fat percentage is your fat percentage, and there will be no fudge factors added because of age.