My new smart scale gave me a body fat reading that was way off

I bought one of those smart scales that connects to your phone, the Renpho one that was on sale for about $60. I set it up last week and the first reading said I had 12% body fat, which seemed really low. I know I'm in okay shape, but that number felt wrong. So I tried it again the next morning, same time, and it jumped to 18%. I did some digging and found out these scales use something called bioelectrical impedance, which can change a lot based on how much water you've had. The lesson here is that these gadgets are good for tracking a trend over time, but you can't trust any single number they give you. Has anyone else found a good way to get a more reliable check without going to a lab?

3 comments

3 Comments

jordan_hill16d ago

So you're telling me my scale might just be measuring how much I've had to drink? That explains why my body fat percentage goes up after my morning coffee. I've had the same issue, and honestly I just use the thing to watch the line go down over weeks, not to trust any single morning's drama. The only reliable check I've found is the old fashioned caliper pinch test, but you have to learn how to do it right or you're just guessing in a different way. Even then, it's a pain and I usually just end up trusting the mirror more than any number.

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owens.blair16d agoTop Commenter

Those scales send a tiny electric current up one leg and down the other, so if you're even a little dehydrated from coffee or salty food, it reads your body water wrong and throws the fat guess way off. I read a study once where people's readings changed just by moving the scale to a different spot on the bathroom floor. Makes you wonder if the only thing they measure well is the battery level.

rose_allen6016d ago

Yeah the battery level thing got me. My old scale would show the low battery symbol for like six months before it finally died. Totally agree with @owens.blair about the spot on the floor too. Mine reads two pounds heavier if it's on the bath mat. I just use it for a rough weight check now and ignore all the other numbers. They cause more stress than they're worth.