Body fat percentage accuracy

Wegowego
Wegowego Posts: 16 Member
in Health and Weight Loss
Hi everyone!

I've been losing weight for 101 days, down just over 15 kilos on a mission to a six-pack. With that in mind I've been monitoring my body fat percentage and after starting somewhere around 25% and a big drop I am trying to figure out where I am now. My bathroom scale says 13.1% my accumeasure calipers with a 7 site skinfold say 9.9%. What should I make of this? Am I somewhere in between the two figures? I'm an active 37 yo male in case that matters. Thanks for your help!

Replies

  • trigden1991
    trigden1991 Posts: 4,658 Member
    All measures of bodyfat have inaccuracies. BIA are the worst and DEXA is the most accurate, with callipers in between. If your mission is to have a six pack, then go by the mirror. Bodyfat is arbitrary for a visual goal as some people have abs at 17% and others don't until 10%.
  • mecoconleche
    mecoconleche Posts: 86 Member
    I'm going for that six pack too, if you can see a blurry four pack you are most likely ~15% body fat.
    Also, track your waist, so once you hit 10% you know how small your waist should be
  • sgt1372
    sgt1372 Posts: 3,997 Member
    edited November 2016
    Multiple threads on this topic. There really should be a sticky to deal w/it.

    The most accurate methods of BF measurement are DXA and hydrostatic w/a degree of error around 5%. DXA tends to give higher BF than hydrostatic. I do both regularly depending on the availability of the mobile vendors that serve my area.

    Calipers and bioelectrical devices are less reliable. Calipers can give reasonably good results but the results are only as good as the person doing the measurements and you cannot do all of the necessary measurements on your own. Bioelectrical devices are the least reliable of the 4. Anything else (like body weight comparison photos) are just a guess.

    I've now got a visible 6 pack (a little better than just a faint image but not high contrast). My last DXA about 2 weeks ago was at 16.9% and my last hydro 6 weeks ago was at 16%. Both measurements are w/in the 5% degree of error. so I was somewhere between those #'s.

    I've just lost about 3 lbs since then but it looks to be mostly fat loss. Based on photos, I should now be under 15%. Due for another DXA in a couple of weeks which will confirm or dispute this impression.


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  • Wegowego
    Wegowego Posts: 16 Member
    Thanks for your replies everyone. BF number matters just out of trying to learn what my body looks like at what percentage. Undoubtedly he mirror is the best and most enjoyable way of seeing results, however, having a scientific mind I love hard data and that helps me always be accountable and motivated to progress.
  • sllm1
    sllm1 Posts: 2,130 Member
    Even though it's the least reliable, the only thing that's easy for me is the scale. I take it with a grain of salt - knowing it's not terribly accurate. (But, as an aside, if DXA and Hydro have a 5% error rate anyway, are they really that accurate? Somehow I thought they would have a smaller error.)

    Anyway, I make sure to do the measure only once every five weeks or so - same time of day each time - making sure it's a time that I'm fully hydrated.

    So, while I'm sure the percentages I get are not terribly accurate, they do consistently show a downward trend and I'm good with that.
  • AnvilHead
    AnvilHead Posts: 18,343 Member
    edited November 2016
    Wegowego wrote: »
    Thanks for your replies everyone. BF number matters just out of trying to learn what my body looks like at what percentage. Undoubtedly he mirror is the best and most enjoyable way of seeing results, however, having a scientific mind I love hard data and that helps me always be accountable and motivated to progress.

    If you want hard data you can compare over time, it's best to choose one method and stick with it. "Man with one watch knows what time it is; man with two watches is never sure".

    Use your skinfold calipers - you already have them and it's easy enough to do a three-site measurement. Is it gold standard accurate? No, but it's repeatable enough (with some practice) to gauge progress over time and at least gives you a reasonable ballpark figure. You can visually tell the difference between, say 15% and 20%. Beyond that, does it really matter if the calipers say you're 15% or 16%? All that really matters is that over time, the trends correlate with whatever your goal is.

    Any method short of autopsy has inherent errors, but taking readings by hydro, DXA, calipers and BIA and then trying to correlate them against each other is an exercise in futility. It's like weighing on three different scales and wondering what your actual weight is or why you randomly gain and lose.
  • GottaBurnEmAll
    GottaBurnEmAll Posts: 7,722 Member
    I had desperately wanted to know a percentage, because I, never having been fit in my life, had a goal of wanting to be classified as "lean" for my age.

    Since no reliable methods of assessing BF are available near me, I've given up.

    I've said this to agree with the other posters in the thread... pick a method like the Navy method or calipers, and then just look for a trend. Combine that with what you see in the mirror. If you're making progress, consider it a win.

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