Bathroom scales that measure body fat?

[kgrogers1979]

I was at Wal-Mart today, and I saw bathroom scales that not only tell you your weight but also your body fat. Do these scales actually work? How can scales tell you how much body fat you have just by stepping on them?

[Thor Simpson]

How Body Fat Scales Work And Why It's Important Body fat scales use a technique called Bioelectrical Impedance Analysis... or BIA for short. Very simply...
A small and completely harmless electrical current is passed through your body. The electrical current passes more quickly through fat free tissue like muscle than it does through fat or bone tissue. So...

The amount of resistance to the electrical current relates to how much fat-free mass a person has and their body density. Here's the first challenge...

Like all body fat tests, body fat scales don't actually measure your body fat percentage. They determine your body density. The examiner (or the scales) then uses a formula to calculate body fat percentage based on body density. Here's the key...

These formulas just predict your body fat. Unfortunately there is no one formula that accurately predicts body fat for the whole population. Differences in age, gender, ethnicity, body size, and fitness level all have a significant affect on the results.

Most body fat scales can account for some of the basic differences such as age and gender, but take the actual body fat percentage they give you with a pinch of salt. What does this all mean for you?

Well, whether body fat scales measure your "true" body fat percentage or not doesn't matter! As long as they can accurately monitor changes in your body composition over time, that's all you need.

Your body position, the amount of water in your body, your food intake, skin temperature and recent physical activity can all adversely affect the results of body fat scales. So...

To achieve accurate, consistent results, you must standardise the way you perform each test. That simply means making each test with your body fat scales as similar as possible. The great thing about body fat scales is...

Standardising each test is easy to do.

Are body fat scales any better than plain old weighing scales?

Absolutely!

[cliffzig]

I have one from Tanita. It's a pretty nice scale actually. You set up your age and body type and what not. When you step on it, it sends low impulse electrical signals through your feet up your legs and down the other leg. By measuring how long it takes the signals to travel, it can get a pretty fair assessment of you body fat %. I have used my scale to see me thru my gastric bypass operation the past 6 months. The body fat % definitely seems to be fairly assessed.

I give tanita the thumbs up.

[BigDave]

Thor gave a great synopsis of those scales.

My wife and I have a two-person Tanita and it works well. It may not show your exact body fat percentage, but you can notice the trends. If I get over a certain percentage then I know I need to really start working out more.

[Thor Simpson]

Originally posted by BigDave
Thor gave a great synopsis of those scales.
I stole it from a goole search. :D

[BigDave]

Originally posted by Thor Simpson
I stole it from a goole search. :D

And to think I thought you had all the amazing info stored in your brain. I feel so cheated. :p

[Jadzia]

I also give a strong recommendation to the Tanita scale.

The body fat reading tends to be more accurate in the evening. I usually weigh myself in the morning, but when I was dieting I would weigh myself twice a day to get both weight and body fat % (since you weigh less in the morning.)

[costanza]

bmi is the only technical reading you need to worry about fatty!!!