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Body Fat Calculator Issues

gunshowgreggunshowgreg Member Posts: 167 Member Member Posts: 167 Member
Hello everyone. I was wondering if anyone here has any experience measuring body fat. so far I have done 3 forms of measurements. I got my skin Calipers in the mail so i was eager to try them out.

I have done

InBody (body scanner at the gym) calculated me at about 21% body fat

Tape Measure style, measuring at my naval 36.5 inches and 15.5 inch neck (below Adams apple) approx. 21% body fat.

Jackson-Pollock 3 Body Fat Formula for Males which estimated me at approx. 16% body fat.
(the average for 3 measurements were Chest 12.3mm, Mid section area 28.83mm, leg 12.16mm)

this last one i found to be a bit irritating because i thought the calipers were gonna be more accurate. granted it was my first time doing it and i was performing the test alone (pretty sure i was doing it right), i just don't think a 5% difference is acceptable. I know looking in the mirror 21% is way more realistic.

my questions are:

1. how accurate is the Jackson-Pollock 3 Body Fat Formula for Males?
2. what measurements does everyone else use and do you use them alone or with assistance?
3. what is your thoughts on in the InBody Scanner if you have ever used one?

32 year old Male
199 Lbs.
5 foot 9 inches

if I left anything out let me know. thanks
edited May 4

Replies

  • davew0000davew0000 Member Posts: 84 Member Member Posts: 84 Member
    Ive been using the JP 3-point.

    My measurements are Chest 9, Abdominal 18, Thigh 12. I’m 41 and 196lbs. My waist around naval is 34.5”.

    I get 13.5%.

    Your body fat calculated with JP3 is surprising. Based on your numbers I’d imagine the 21% is closer to the mark.

    You’ve made me wonder how accurate my own calculation is, to be honest.

    I’m not answering your questions but I thought you’d be interested in another person’s JP measurement.
  • gunshowgreggunshowgreg Member Posts: 167 Member Member Posts: 167 Member
    davew0000 wrote: »
    Ive been using the JP 3-point.

    My measurements are Chest 9, Abdominal 18, Thigh 12. I’m 41 and 196lbs. My waist around naval is 34.5”.

    I get 13.5%.

    Your body fat calculated with JP3 is surprising. Based on your numbers I’d imagine the 21% is closer to the mark.

    You’ve made me wonder how accurate my own calculation is, to be honest.

    I’m not answering your questions but I thought you’d be interested in another person’s JP measurement.

    heck yea boss I really appreciate it. its important to note that i also used a calculator online to punch in the #s to get my body fat %. I don't think that was big deal but I'm not sure
  • cwolfman13cwolfman13 Member Posts: 39,106 Member Member Posts: 39,106 Member
    I've only ever had my trainer do it. He uses calipers and uses the Parillo 9 site skin fold test and has a ton of experience doing it as a long time personal trainer, retired professional athlete, and one of the team USA Supercross BMX coaches. He can also visually tell pretty close. First time he did mine years ago he estimated around 15% and the calipers gave him 15% afterwards so I don't think he or his method are that far off. I'd personally not do my own...I've tried and I can come up with my own different numbers. I think a non-biased professional is better. That said, I also don't think it's particularly important to know the number...I've only had him do it a couple of times in the 6 or so years I've known him. I pretty much just look in the mirror.
  • sgt1372sgt1372 Member Posts: 3,877 Member Member Posts: 3,877 Member
    Calipers are hard to use accurately and, as @cwolfman points out, are best used by someone with training/experience using them. The more points of measurement the better and, for the greatest accuracy, you cannot possibly do them all by yourself.

    Tape measure/BF calculators are just ball park estimators and cannot possibly give an exact result for anyone. The same applies to retail bioelectrical devices.

    The most accurate way to measure BF available to the pubic is either hydrostatic weighing and/or DEXA. I've done both. Results are correlated but not identical.

    Hydro generally gives lower results. Every calculator and bioelectrical device I ever used gave me a # higher than what I got w/hydro or DEXA.

    However, hydro only provides a basic BF vs nonBF mass info. DEXA will give you BF, nonBF and bone mass/density data, BF distribution info, including VAT which is much more useful.

    DEXA is also much more convenient to do than hydro. You can just lay on the table in your skivies to get a DEXA scan done in a few mins but you have to get into your bathing trunks and get dunked under water (usually 3 times) while you try to expell as much air out of your lungs possible each time (which is a source of error) to get a BF% result in about 15-20 mins.

    Of course, the other problem w/hydro and DEXA is cost/availability but, if you have the $ and access to either of them, I'd recommend them over any other method of BF "measurement."
    edited May 5
  • davew0000davew0000 Member Posts: 84 Member Member Posts: 84 Member
    To put in a positive case for callipers...

    I have found my measurements to be quite consistent. In statistical terms, the variance of the measurement error is low. For example, I got a remarkably consistent lean body mass when on a recent cut.

    There may be a significant bias to my estimate but I’m not too concerned about that. I’m interested in tracking progress over time. And actually, comparing myself to photos of people in the 13-16% range, my measurements look about right.

    I do wonder if such methods don’t work so well with people with a large amount of visceral fat.
  • sijomialsijomial Member, Premium Posts: 18,363 Member Member, Premium Posts: 18,363 Member
    "my questions are:

    1. how accurate is the Jackson-Pollock 3 Body Fat Formula for Males?
    2. what measurements does everyone else use and do you use them alone or with assistance?
    3. what is your thoughts on in the InBody Scanner if you have ever used one?

    32 year old Male
    199 Lbs.
    5 foot 9 inches

    if I left anything out let me know. thanks
    [/quote]


    1/ The more sites the better - not everyone has the same body fat distribution. And it's far better to get it done by someone else and preferably a trained person. I'd be very dubious about just 3 points and even moreso a DIY 3 point reading.
    2/ The mirror basically! I'm not that fussed about a number, especially a number that can have quite a wide margin of error. I can see if my body fat is up, down or staying roughly where I want it. When I was overfat I could see I was overfat so knew the direction needed. Taking and reviewing progress photos also works if you are still in your weight loss phase.
    3/ I sometimes use a Boditrax which is I believe similar to the InBody. Four point contact points far superior to machines with just two. But still needs to be used with attention to consistency to avoid the general BIA issues of varying hydration levels messing up the numbers (think fed or unfed, recently exercised, different times of day....). A reasonable/believable trend but with some weird and wonderful odd readings along the way. It's free at my gym but I wouldn't pay for it. Absolutely not good enough to just wander up and use it at random or once and expect accuracy.

    61 year old male
    170lbs
    Also 5'9"

  • heybalesheybales Member Posts: 18,735 Member Member Posts: 18,735 Member
    https://exrx.net/Calculators/BodyComp

    Shows study on accuracy of the different site methods at the bottom.
    And a calculator.
    Which as mentioned unless you are skilled, could be very iffy.

    Throw that and the measurement method together and avg them out - and track for awhile.
    http://www.gymgoal.com/dtool_fat.html

    For measurements - if you have a body part used you know is outside avg norms, it'll throw it off. Like some may have very big calves even at healthy weight, that'll throw that calc off.

    Exact accuracy is unlikely needed, direction is desired.
  • gunshowgreggunshowgreg Member Posts: 167 Member Member Posts: 167 Member
    ok guys I F'd up. i went back and did the pinch properly (or better than i did before) my end results got my to about 22% BF. that is way more realistic. I'll be honest YouTube was my trainer in this and the first one for whatever reason caused me to mess up. I guess i couldn't see where the pinch was. the second video i found to be much more helpful and showed how to do it with better instructions. the only fault in this was operator error. sorry to waste anyone's time.

    1st video. this one kinda messed me up, but it could have just been me.

    2nd video. i thought he did a good job explaining in this video

    in case anyone was interested
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