How accurate are body fat measuring scales?

fitnessqueen91
fitnessqueen91 Posts: 166 Member
edited December 21 in Health and Weight Loss
I went to Boots Pharmacy to check to see how my body fat percentage is doing. Last month it was around 29%. This month I've been doing even more weights and exercise and haven't cheated at all on my diet. I measured today and it came up as 30% BF. I measured again and it went down to 29.4% and the 3rd time 29.8%. I feel that I've been working so hard and my body fat percentage is still high. I was expecting 27-28%. It was one of those scales where you grip handles which send a current through your body. I'm really confused as I feel more toned.

Replies

  • eeanneli
    eeanneli Posts: 35 Member
    Very inaccurate. It is an electrical impulse and it guessing composition based on resistence. Things like your hydration level hugely affect it.
  • MichelleSilverleaf
    MichelleSilverleaf Posts: 2,027 Member
    DEXA scans and I think there's another type are pretty much the only ones that are relatively accurate. The rest (including the one you describe) generally are not. I would go by measurements and appearance in your case, take progress pictures if you don't already and see that trend over time.
  • snickerscharlie
    snickerscharlie Posts: 8,578 Member
    fitnessqueen91 wrote: »
    I went to Boots Pharmacy to check to see how my body fat percentage is doing. Last month it was around 29%. This month I've been doing even more weights and exercise and haven't cheated at all on my diet. I measured today and it came up as 30% BF. I measured again and it went down to 29.4% and the 3rd time 29.8%. I feel that I've been working so hard and my body fat percentage is still high. I was expecting 27-28%. It was one of those scales where you grip handles which send a current through your body. I'm really confused as I feel more toned.

    Just keep doing what you're doing and leave the scale at Boot's alone. They're notoriously inaccurate. ;)
  • tcunbeliever
    tcunbeliever Posts: 8,219 Member
    My body fat scale is consistent if I use it first thing in the morning, and the instructions are very clear about how you need to have zero clothing on for a good measurement, so I'm guessing you weren't naked at the pharmacy!!!

    That being said, take measurement at multiple places on your body, and track your weight, and you should be able to see your body fat % improving over time, not matter what the pharmacy device says.

    The average person can metabolize about 1% body fat per week, so after a month you really should see a change in your size - how are your clothes fitting?

    Even DEXA can be off by +/-5% which is a lot for something that comes with a high price tag.
  • fitnessqueen91
    fitnessqueen91 Posts: 166 Member
    Haha the comment about being naked pharmacy made me laugh :lol: Thanks for your answers guys. My clothes are much looser; I've had to go shopping for new clothes in fact! I was really discouraged by the Boots body fat scale, but it's good to know that they're not that reliable and it's not me. I don't know if they also assume your body fat based on BMI. My BMI is 25.5 so maybe they assume because my BMI is overweight that I have more body fat. I don't know.
  • NovusDies
    NovusDies Posts: 8,940 Member
    Read the post by @sanderds:

    https://community.myfitnesspal.com/en/discussion/comment/43583412/#Comment_43583412
  • shadow2soul
    shadow2soul Posts: 7,692 Member
    edited May 2019
    Both of what you’re describing are using Bioelectrical Impedance Analysis. It’s not known for it’s accuracy. According to one manufacturer of the handheld devices they can be thrown off by hydration levels and if you have eaten recently.

    I have 2 devices that use this method. A scale and a handheld device that I hold to different muscles to get a reading (overall BF% estimation requires a scan at triceps, abdomen, and quads).

    I used both yesterday morning and I got 2 different results.
    Scale: 30.6%
    Handheld: 29.9%

    With the handheld I did a full body scan (doesn’t improve accuracy of BF% estimation..still only uses the 3). Averaging out the individual BF% numbers I got for my calves, glutes, hamstrings and quads I get the 30.6% the scale gave me. It’s interesting that the handheld device seems to show that the scale is stopping its reading around my hips. It may be coincidence, but it seams to be that way every time I have actually compared the two.

    That said, while I do use them as a rough guideline along with measurements and pictures I don’t believe they are all that accurate.
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