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Body Fat Percentage Scales

Yesterday I wrote about how your Body Fat Percentage (BFP) is a more accurate way to measure excess body fat when compared to your BMI. The New York Times reported recently that some studies suggest that BFP is a better indicator of health than your weight.

Underwater weighing is considered the most accurate method for determining your BFP, the more body fat you have the less you weigh in water. This method costs about $200 a pop. So it is not surprising that sales of scales with built-in body-fat monitors using bioelectrical impedance are up. They work by measuring how fast an electrical signal travels through your body. The more muscle you have the faster the signal travels. Fat contains almost no water, while muscles are about 70% water and water conducts electricity that is why the signal moves more quickly through muscle. If you are dehydrated you will read as having a higher percentage of fat (another reason to stay hydrated).

These types of scales were first introduced in the early 90s but the technology has improved and the scales are less expensive now. There are many out there on the market ranging in price, starting with the Health O Meter BFM-687 (I just love the name of this scale - it sounds so very 1950s sci-fi) for $34.98 found at Sam’s Club stores. Going more upscale if you will, there is the Tanita Innerscan BC551 for $139.99 available online at the competitive edge.

NY Times gave both scales good reviews, when tested for accuracy they both measured within a variable range of 4 percentage points of accuracy.

Join The Conversation
BlondeSugar BlondeSugar 10 years
I have one, but I know it's 3-4% off so I just subtract that amount. Kind of sucks, but at least I know where I stand.
princessbummi princessbummi 10 years
wow. i always wondering how one of those things worked. i knew they existed because i had friends tell me that they went to a fitness depot that sold those scales. A few weeks ago i was telling my boyfriend about it and he didnt think it was possible that there was some sort of scale that you could buy that would measure body fat. cant wait to show him this article. its time to prove him wrong. “Whoever said money can’t buy happiness simply didn’t know where to go shopping” - Bo Derek
aragornrain aragornrain 10 years
Wow, 4% off is a lot. That's enough to put someone into the unhealthy range when they really aren't (or the other way around). It would be pretty tough to track fat-loss if you never knew if you could trust what the scale said. Plus, how would you know if it was 4% off on the high or low direction? That means if it told you 25%, your body fat could really be anywhere from 21-29%. Pretty useless.
klgibian klgibian 10 years
My husband and I have one of these - when we first set it up, we had to input things like age, sex, height, and activity level. At first we both put in "athlete," because we do triathlons and work out hard 5 or 6 days a week. But then we read the instruction booklet, and it says an "athlete" is someone who works out 10 hours or more a week. Anyway, under the "athlete" categorization, both of our BFPs were considerably lower than under the "very active" categorization. Presumably it is assuming that if we're true athletes, our weight is attributable more to muscle than to fat. But if this thing really does use a current to measure BFP, that shouldn't matter, right?
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