When a celebrity we love asked how our scales measure body fat we had to answer the call. In this case “the call” was actually a tweet, but still. Find out what goes into the number you see on your scale and in your app, below.

Once upon a time (yesterday), writer/comedian Mike Drucker shared a pic of his new Nokia Body+ scale and Steel HR hybrid smartwatch on Twitter:

Well, time to try to make myself less of myself so I can wear video game shirts without people being like, “We already knew.” pic.twitter.com/bok447vcly

— Mike Drucker (@MikeDrucker) March 8, 2018

Then writer/performer Kumail Nanjiani responded with a serious question:

Real question: How does the scale know body fat percentage?

— Kumail Nanjiani (@kumailn) March 9, 2018

Of course because this was asked in comedianland, there were some interesting responses. Answers included “it feels our shame” from @CountRapula to “Doesn’t it come with a guy? He just hangs around the scale with a caliper and waits” from @ElectroLurk.

So, amazingly, neither of those responses were right. Here’s what really happens when you step on:

Our scales that measure and track body fat are Body+ and Body Cardio. These models use the Bioelectrical Impedance Analysis (BIA) method. The scale sends a tiny current that allows it to measure your impedance which can then be used to calculate an estimate of total body water.

Total body water can be used to estimate fat-free body mass and, by difference with body weight, your fat mass.

If you want to go deeper, one thing to note is that fat mass + bone mass + muscle mass = 100% of body composition. Because water is in muscle and fat, water mass cannot be added to the other metrics when calculating the body’s composition.

It should be noted that all our scales are highly accurate, automatically sync to the free Health Mate app, and can track up to 8 users with independent sync—so if you have one, you could, say, share your scale and track your data alongside all the leads on HBO’s Silicon Valley, for example.

Our scales also offer a localized daily weather report on screen. And all of our scales offer baby mode and pregnancy tracker. Actually, “baby mode” is also popular as an off-label use with pet owners, and we personally love when our users share their pics on social, so please keep those coming.

So we hope we’ve answered the question about body fat. Here’s a link for anyone who wants to see our smart scales.

Source: Withings Blog
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