Body fat scale?

I keep seeing the step on or hand held devices that claim to measure body fat but I can't imagine how they could possibly be accurate. Does anyone have any experience with these and their accuracy? Know how they work? Just curious of the technology behind them and if this type of monitoring is possible.

Thanks!

In theory they work by sending electic pulses through you, and BF% is estimated by the speed at which it travels as fat and muscle impedes the electricity differently. The biggest issue with these are that hydration levels can impact the results, as well as the amount of undigested food in your system. That said over time if it is trending in the right direction you are making progress. Just try and measure in the same situation each time (time of the month for a woman, fasted, and hydrated).

I have an Omron hand held and while it isn't entirely accurate, it does give me a number that I compare each month. And it is cheaper than paying to have my BF% analyzed each month. I do pay to have it done a couple of times a year though, but I do rely on my hand held for regular comparisons.

The send a low level electrical pulse through your body (you can't feel it). This pulse will travel from one hand to the other (or foot) and the amount of time it takes will vary depending on water, fat and muscle in your body (each has it's own resistance). It takes your height, weight and age into account. This is so it can take your bone density out of the equation.

It would say it is a good tool but no it isn't 100% accurate. It tells you more of a story that just your weight. Your weight may go up, but you body fat can go down. This would mean your you either have water weight or gained muscle. Calluses on your hand or feet can impede the signal which will skew results. But these should stay relatively the same between measurements so you can still get an idea of going up or down.

It will be be much more accurate than BMI. I asked my DR about them and she said they are the most accurate thing you can do yourself for measurements. Anything more and you have to do the calipers or dunk tank at a Doctor's office.

If you are going to use this, use it in the morning before drinking and eating anything (I have noticed body fat will go up a little bit if your stomach is full) and if possible after you have used the bathroom. Doing this will give you a more accurate gauge of your body specifically. Also occasionally clean the metal surfaces because dust and other things can impede the signal as well.

Edit: Groupon often has the scales on a few times a year for under $20. These also estimate your hydration level.