[QUOTE=sdc100, post:6, topic:407418]
This is a nice motivator, if only because it’s fun and provides feedback. But don’t expect any of these BIA scales to be very accurate in measuring fat, muscles or bones. We tried them in a study on HIV wasting, and they were judged too irreproducible and variable to be medically useful. We ended up with a professional model which requires lying down and measures electrical flow from the fingers to toes. That gives a more accurate picture since the electrcity travel through most of the body, Handheld and scale models only measure the top or bottom halves of the body.
The biggest problem with these BIA machines is that they don’t measure fat, bone or muscles at all. They estimate water contents based on the impedance, or how much the electricity is impeded as it goes from point to point. The more water you have, the less impeded the electricity. Since muscles are composed mostly of water and fat contains very little water, electricity will flow faster through muscle than fat (fat is an insulator … that’s why our neurons are encased in lipid). An internal formula then guesses how much fat you have based on a database that was compiled using the averages of others with your age and sex.
For accurate measurements, you really need to measure yourself under identical conditions each time. Ideally, you should have an empty bladder and stomach (water in the intestines decreases impedance, confusing the scale). And no alcohol.
Even with professional models, we realize that it’s not a perfect measurement of body fat (most accurate are DEXA or water displacement tank). BUt they are very useful at keeping track of trends, i.e. more fat, less fat. And they are a nice motivator because you can watch the relative fat levels rising or falling. This unit is especially nice because you’re not limited to what’s in the scale. The software can be adjusted or replaced as necessary.
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I can’t remember but having a pacemaker (or any other electrical implant, i.e. insulin pump?) might disqualify you from doing BIA. So be careful.
Metal implants, i.e. hip or knee replacements, might also affect the result since metal is an excellent conductor (even better than water!). Check to be sure. Breast implants shouldn’t matter though since they’re upper body and the liquid is enclosed in an insulator.
Those who can’t do BIA may still be able to use this as a regular scale though (am unsure if you can turn BIA off. Most BIA scales have that option). Tracking your weight alone is still helpful for weight loss (or weight gain). And $39 is still a good price for a non-BIA Bluetooth scale.
Sorry, I can’t be more informative but I haven’t done BIA in 10+ years.