Question on Body Fat Scales

You want to be more hydrated. The less hydrated you are, the higher they read your body fat.

They aren't actually all that consistent either. I weigh myself every day and my body fat % varies by up to 4% over the course of a week. That's a 5-6 pound difference!

This.  Then watch the trends...don't worry about daily fluctuations.

Wake: take measurement

record %fat

Drink water: take measurement

note change in %fat

Below is a 3 part article on the accuracy of the scales.  I have one, its terrible.  I would guestimate myself in the 14%ish range.  Scale tells me in the summer time well hydrated that I am 13% using the normal setting and 6% using the athlete setting.  If I am not well hydrated then I see more like 9% on athlete mode and 17% on normal mode.  For some reason in the winter when its cold and dry my percentage body fat goes up by 3-4%, 19-20% on normal mode isn't unusual for me to see this time of year with no change in body weight or any visual sign that my body comp has gotten worse.

http://www.dcrainmaker.com/2011/08/bod-pod-consumer-scale-comparison-tests.html

http://www.dcrainmaker.com/2011/08/bod-pod-consumer-scale-comparison-tests_25.html

http://www.dcrainmaker.com/2011/09/bod-pod-consumer-scale-comparison-tests.html

I think the Tanita body fat scales (I have the BC-554) are very consistant and a good measure of your body fat.  Accurate?  Have no idea, but consistant yes.

I weigh myself first thing in the morning after morning pee and my fat numbers reflect what I see in the mirror.  When training is in full swing, my body fat is around mid 10%.  Right now as I gained a "few" holiday pounds in my gut, the scale is showing mid 12% which corresponds to the new notch I am using on my belt. 

I know if i wait an hour or so after I get up and have a drink, the body fat % comes down due to hydration and is probably a closer to "real" BF %.  If I just come back from a run the numbers can be all over the place defending on my much I sweat.  But if I weigh myself first thing in the morning, I can defeinately tell if my body fat is up or down.

I use to use a Tanita, but there was a flaw in manufacturing (wasn't sealed well) that they wouldn't do anything about (not just me, but endless people hosed by Tanita).  The scale lasted about 2 months then stopped working.  I now have Omron. 

The Tanita scale gave me BF% about 6% higher than the pinch test I had done by my nutritionist.  The 6% is an average of 5 compared tests.  The Omron is about 3% higher than Tanita, thus I discount the # by 9%.  

I'm not so concerned with 100% accuracy as I am the trend.  I just wasn't sure how hydration impacted those scales.  Thanks for providing those articles, I'll definitely read them.   

To know when to go on a diet/adjust my eating habits.  I don't care about a 3-4 lbs gain during marathon training.  I do care about a 1-2% fat increase around the holidays.

Same reason people want to know heart rate, power output, cadence, and any other metric. How skinny is too skinny? How much can I safely lose? How is my weigh loss coming?

I've had a Tanita for a long time. My experience is like most others - not an accurate number, but the consistency is good so it's good for tracking trends. Mine tells me I'm currently 4-4.5%. I'm nowhere near that, probably more like 9%. But as I've lost weight, it has shown a similar decrease in BF%.