Body Fat Scales Warning

They are useful for tracking trends, given the same measuring conditions every time.

If you use the same ruler for every job, it doesn't matter as much if the inches are wrong.

They can be handy for tracking progress. It's pretty well documented that the number they give you is next to worthless, but if the number changes, then that usually reflects an actual change in body composition (assuming that you always use it with your body in the same state as far as hydration, time of day, etc).

For example, my body fat according to calipers is down to 22%, from 29%, which judging from pictures is pretty accurate for me. My body fat scale has gone from 37% to 30%. So it's about 8% high, but it's consistently 8% high.

I rely mostly on the BF % taken by my trainer, but I know a lot of folks don't have that option. I also have a FitBit scale. I don't know how accurate it is (I unfortunately can't remember my BF % my trainer took) but I do know that it's gone down from two weeks ago (from 38% to 35%... I'm a work in progress:embarassed: )

I mainly look at the change in BF on the scales. If it goes down--I know I'm on the right track!

As melanie cheeks states, BF% *is* incredibly difficult to measure accurately.

I have the Aria, and I don't really worry too much about the BF% number it reports. I know it can't possibly be accurate - but that said, i would expect it to be a good indicator of my BF% *trend* - that and other external indicators let you know if you're moving in the right direction.

WOOPS!!! LOL... sorry!!:blushing:

I use caliper and visual inspection. The Trend of the number (excellent verbage k8) is the most important, however I have a close to specific number that is my goal, just out of curiosity to see what happens to my c section belly...

The only truly accurate ways to measure bodyfat is a displacement method - either air (aka bodpod) or water - if you have a university near you with an Exercise Science department you can probably get this done for $50-100, depending on where you live (the university near me charged $50 the last time I had it done)...or a DEXA scan (Dual Energy X-ray Absorptiometry) - which is difficult to find and pretty expensive (like $250+).

The second most accurate method is skinfold testing, with the skin fold measurements being taken by someone who has been trained on how to use the calipers (and preferably to have the same person take the measurements each time). This is probably the most accurate method for the majority of people, because any personal trainer worth their salt at a local gym *should* know how to do skinfold testing.

Bioelectric Impedance methods (BF scales or those handheld devices) are basically the least accurate (outside of the US Navy calc using waist/neck/height for men and hips/neck/height for women). The results can vary significantly, depending on how hydrated you are...and can be off by anywhere from 5-10%! These methods are best used for tracking BF trends, as opposed to actual BF %, provided that you are measuring using the same hydration levels each time (ie you'll know that your BF is decreasing over time, but you won't know your *actual* BF %). Not to mention the fact that BI methods are known to be completely inaccurate for people with very low BF.

HTH!

It is also pretty well established that these scales also confuse water for fat. As for people who tend to have eating disorder tendencies...they tend to have them regardless of what a scale says anyways; the scale could say they're 85 Lbs and 5% BF and all they would see in a mirror is a fat person.

Personally, I just use the mirror and a decent set of calipers to give me a reasonable estimate...I don't need an exact number. I can see whether my body composition is improving or not.