Has anyone used body fat scales and know if these are reliable? These are digital scales that look just like weight measuring scales that you just step on?
Has anyone used body fat scales and know if these are reliable? These are digital scales that look just like weight measuring scales that you just step on?
I think these devices use technology called Bioelectrical Impedance Analysis (BIA) which I will try to do some research on...well at least some online research.
the commercially available scales are pretty unreliable, hydration is the great leveler of BIA scales. skinfolds by an experienced technician is the cheapest way to go.
But it seems like skinfolds change during the day...so do we fast before the test?
The skinfold thickness doesn't change all that
much (it is much less susceptible to changes during
the day than bio-electrical impedance). Keep in
mind you are just measuring the thickness of the
skin and the subcutaneous fat-layer attached to the
skin, not the muscle, so while the muscle volume changes
a lot based on hydration-levels, body-temp, etc..., the
skin thickness doesn't change as much. Just make sure
that you let the calipers stay pinched for a good 10
seconds or so before you record the reading - this will
allow time for any extra water to be squeezed out.
For practical regular testing, skinfold testing is
the way to go. It won't tell you exactly what your
body-fat percentage is (total body-fat percentage
as a function of skinfold depth varies from person
to person by a fair amount), it is quite accurate for
doing comparisons from one day to the next on the
same person, provided you do the test at the same spots
(typically chest, abs, and thighs for men) and the
same person does the test each time (you can easily do
these three spots yourself). Just measure the thickness
of these three spots, add up the numbers and write this
total down. Repeat once or twice a week, and over time
you will easily be able to see how your body-fat is
changing (if it is). Don't rely too much on your first
few readings, as it will take a few times for you to
get consistent in how you do the test.
Forget about what bodyfat % these numbers correspond to -
there is no way to know for sure within closer than +- 3%,
and bottom line is - who cares?