Fitbit Scales

[Drew8686]

How effective are the Fitbit scales. It claims to measure Body Fat but how accurate is the measurement? is it worth the purchase?

[divedragon]

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@franksj wrote:

Hi Jennifer!  

Great to have you here.  Did you put your scale into Lean mode?  It sounds like the setting for you.

Also, the scale calculates fat % by passing a small current through your feet and measuring the amount of impedance (resistence) your body provides.  I imagine such a calculation has quite a number of assumptions that may or may not be true for you. I wonder how such a reading could change based on hydration and mineral levels.  

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Impedance measurement of bf is common and notoriously inaccurate.  It's a gimmick for the scales, so I wouldn't rely on it.  The weight is pretty accurate though.

[Paradise555]

The fitbot aria is actually pretty accuate for weight but for body % is horrible. If you ware trying to lose weight then it is a very good tool to have in your "toolkit".

[cheri123]

I got the scale.  It works like a regular scale.  Had a hell of a time setting the blasted thing up.  It does not sync with my profile.  Am I happy with it?  No. You have to be a freaking computer genius to work it.  I am so glad I did not use real money to buy it.  I used some kind of reward points.  Maybe some genius at Fitbit will call me and assist me, but right now the techs are extremely unavailable.

[Dominique]

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@Paradise555 wrote:

The Fitbit Aria is actually pretty accurate for weight but for body fat % is horrible.

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In what way are the body fat measurements "horrible"? I’ve seen many people reporting wild fluctuations of body fat measurements. This hasn’t matched my own experience. As an example, here are my weekly averages (I weigh every morning in the same conditions) for the past nine weeks:

week1: 66.7kg/17.9%

week2: 66.6kg/17.8%

week3: 65.6kg/17.8%

week4: 65.3kg/17.4%

week5: 65.5kg/17.0%

week6: 65.5kg/17.1%

week7: 65.5kg/17.2%

week8: 65.1kg/17.2%

week9: 64.3kg/17.0%

I can’t say whether the body fat estimation are "accurate" in absolute terms, but they are certainly consistent, and in line with what you’d expect (lower weight = lower BF%).

[Dominique]

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@divedragon wrote:

Impedance measurement of bf is common and notoriously inaccurate.  It's a gimmick for the scales, so I wouldn't rely on it.

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I’ve been using an Aria for close to three years, and the body fat % values estimated by it have worked pretty well for me. You can see an example of weight and BF% values observed over a nine weeks period in this other post of mine.

[yountdw]

I had a lot of trouble setting mine up, too. A tech could not get it done. After he gave up, I figured it out. If you are still having trouble, reply, and I will try to locate the instructions I used. The instructions have to be followed precisely, and in the proper order. Good luck.
The good news is that you can do it, and that thereafter it will sync with your phone and computer.

[lynnbaum]

For all of us out here that are looking at your BF % we all say I am glad you got your to work,   I think there is something wrong with mine because it says. 37%.  I am a 5" tall female.  Bite me.  Seeing 17% would be a dream of mine.  I do the same as you.  I compare the changes.

BTW no problems when I set it up on XP first and then I Got new computer with 8.  No problems.  Don'y over think when installing.

[Dominique]

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@lynnbaum wrote:

I compare the changes. 

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It’s the right approach IMO. Have you found changes in estimated BF% to be in line with changes in weight?

You may also want to have a BodPod or DEXA scan made, to establish the discrepancy between BF% reported by the Aria and your actual BF%. 

One of the most reliable way to estimate BF% at home is supposedly the BodyMetrix Personal System. It’s quite expensive, though.

[lynnbaum]

Good answer.  Comparing it to a bodpod or even a personal trainer test is something I do with my scale.  Also I see by your picture, you work out more than I do.  Sometimes what we want the scale to say and what it really says are 2 different things.  As my weight goes down the BF% goes up so you are correct it is directly related to weight.  This is the reason why lifting weights is so important.

[Dominique]

In principle, your BF% should come down as you lose weight (at least, you want your weight loss to me mostly fat), but it’s not that straightforward (with the Aria). If you look at the series of data I posted:

first week of February 2016: 66.7kg/17.9%

first week of April 2016: 64.3kg/17.0%

This would suggest my body fat went from 66.7 x .179 = 12.1 to 64.3 x .17 = 10.6 kg (= 1.5 kg fat loss), while my lean mass went from (66.7 - 12.1) = 55.6 to (64.3 - 10.6) = 53.7 kg (= 1.9 lean mass loss). In other words, according to these numbers, my 3.4 kg total weight loss would be 44% fat loss and 56% lean mass loss. I certainly hope it’s not the case!

I try to get visual clues of my body fat, for instance by looking at veins on my arms. I’m now starting to see to some extent veins on my biceps area, which I couldn’t see when 3-4 kg heavier:

These are changes the Aria may not necessarily detect. I may also buy a caliper, as these are cheap and allow for measurements in different areas of the body. The BodyMetrix device would be nice, but I find it too pricey for my purpose.  

[smileyme]

what is the water displacement method?

[Dominique]

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@smileyme wrote:

what is the water displacement method?

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Also known as "hydrostatic weighing", it’s a very unpractical method. See get weighed underwater for more explanations.

[yountdw]

One way of gauging body composition (i.e., muscle vs. fat), is to be immersed naked in a tub of water and see how much water your body displaced. Then using some formula, you can get a most accurate measure of body composition. It is much more accurate than the caliper methods used in most instances for convenience.
At a high end gym, or perhaps at a sports medicine clinic, you could obtain such an analysis.