Body Fat %

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13

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  • JeffseekingV
    JeffseekingV Posts: 3,165 Member
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    squirrelone wrote: »
    Calipers are really the only way to go. They are the accurate (for home use) and so cheap that there is no good excuse to not use them.

    I have one of those silly scales that supposedly measure a million things. It says 10.5% while the calipers say 7%.

    How do you know which is accurate?
  • lorib642
    lorib642 Posts: 1,942 Member
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    __drmerc__ wrote: »
    My DEXA and handheld bf impedance thingie were within 1-2%
    I don't think they are as inaccurate as most here lead you to believe

    That is good. Is it new? My scale is about 10 years old.
  • Wheelhouse15
    Wheelhouse15 Posts: 5,575 Member
    edited November 2014
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    __drmerc__ wrote: »
    My DEXA and handheld bf impedance thingie were within 1-2%
    I don't think they are as inaccurate as most here lead you to believe

    It depends on how close you are to the models they have programmed into the algorithm. If you are close to what they have, and on the top or bottom since electricity takes the path of least resistance, then you will be closer to the gold standard. Those of us who are not within a reasonable distance to their model for age, sex and height will be off considerably.

    Here is a paper that shows that BIA tends to be off around the 5% range from DEXA.

    jap.physiology.org/content/64/2/529

    ETA Note that they seem to use BMI as their fat estimation since they are close to that.
  • Wheelhouse15
    Wheelhouse15 Posts: 5,575 Member
    edited November 2014
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    Double.
  • squirrelone
    squirrelone Posts: 58 Member
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    JeffseekingV wrote: »

    How do you know which is accurate?

    Calipers are the tried and true method.
  • Wheelhouse15
    Wheelhouse15 Posts: 5,575 Member
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    squirrelone wrote: »
    JeffseekingV wrote: »

    How do you know which is accurate?

    Calipers are the tried and true method.

    The paper I linked above shows calipers to be more accurate; however, they use the seven fold test that you normally get at a gym. GNC calipers claim to be within the same level of error or better. Not sure but they do put me closer to the tape measure method than my scale.
  • JeffseekingV
    JeffseekingV Posts: 3,165 Member
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    squirrelone wrote: »
    JeffseekingV wrote: »

    How do you know which is accurate?

    Calipers are the tried and true method.

    calipers are only as accurate as the person doing the measurements are. The best way to confirm one of your methods by getting a verified measurement done and compare it to your methods.

    If you are really 7.5%, post a picture, I'd really like to see that.
  • Wheelhouse15
    Wheelhouse15 Posts: 5,575 Member
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    JeffseekingV wrote: »
    squirrelone wrote: »
    JeffseekingV wrote: »

    How do you know which is accurate?

    Calipers are the tried and true method.

    calipers are only as accurate as the person doing the measurements are. The best way to confirm one of your methods by getting a verified measurement done and compare it to your methods.

    If you are really 7.5%, post a picture, I'd really like to see that.

    You are correct, calipers can be an issue if you don't do them properly since even a small move can make a difference. That's why I use both tape and calipers. I generally get about 0.5 - 1% higher on tape.
  • Wheelhouse15
    Wheelhouse15 Posts: 5,575 Member
    edited November 2014
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    __drmerc__ wrote: »
    Wheelhouse15 wrote: »
    __drmerc__ wrote: »
    My DEXA and handheld bf impedance thingie were within 1-2%
    I don't think they are as inaccurate as most here lead you to believe

    It depends on how close you are to the models they have programmed into the algorithm. If you are close to what they have, and on the top or bottom since electricity takes the path of least resistance, then you will be closer to the gold standard. Those of us who are not within a reasonable distance to their model for age, sex and height will be off considerably.

    Here is a paper that shows that BIA tends to be off around the 5% range from DEXA.

    jap.physiology.org/content/64/2/529

    ETA Note that they seem to use BMI as their fat estimation since they are close to that.

    Study shows exactly what I said, about 1-2%. Did you even read it? or just not understand it?

    "The BIA, skinfold fat, and hydrostatic methods were all found to be reliable (Rxx = 0.957–0.987) with standard errors ranging from 0.9 to 1.5% fat"

    " The standard errors of estimate for the two BIA models ranged from 4.6 to 6.4% fat compared with 2.6 and 3.6% fat for the sigma 7 equations. "

    Oh, sorry, I was skimming. Good catch I normally don't mistake those measurements.

    ETA I also believe that was the tetrapolar since it is more accurate than LL HH methods.
  • squirrelone
    squirrelone Posts: 58 Member
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    JeffseekingV wrote: »
    calipers are only as accurate as the person doing the measurements are.

    This is very true. Which is why I would always advise getting someone who knows what they are doing, to help.
  • lorib642
    lorib642 Posts: 1,942 Member
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    Is this something where YMMV or is my scale just really inaccurate?
  • Wheelhouse15
    Wheelhouse15 Posts: 5,575 Member
    edited November 2014
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    lorib642 wrote: »
    Is this something where YMMV or is my scale just really inaccurate?

    It depends on how close you are to the models in the algorithm used. This is why certain people find them more inaccurate than others.

    Here is an article that explains a bit more about the different types and their accuracies.

    formulamedical.com/fORMULA%20FOR%20LIFE/measurement&diaries/BIA.htm
  • lorib642
    lorib642 Posts: 1,942 Member
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    Wheelhouse15 wrote: »
    lorib642 wrote: »
    Is this something where YMMV or is my scale just really inaccurate?

    It depends on how close you are to the models in the algorithm used. This is why certain people find them more inaccurate than others.

    Thanks.
  • 04hoopsgal73
    04hoopsgal73 Posts: 925 Member
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    I can lose weight slowly and have taken off lots of body inches. Body Fat % barely reduces in comparision to those metrics....
    Once a month the nutritionist uses a Tanita scale at the women's studio. I just keep eating well and know it will all come together over time.
  • fatcity66
    fatcity66 Posts: 1,544 Member
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    Wheelhouse15 wrote: »
    JeffseekingV wrote: »
    I'm not rich so I can't afford to have multiple DEXA scans done at $150 a pop. I'd probably advocate ONE scan and then immediately do a bioimpedence scale, calipers, hand held bioimpedence etc... then compare the two for reference.

    It's not really the accuracy perse as long as it's consistent. If it's consistent, then the DELTA change in bodyfat is what is important.

    When the reliability of these scales is in question even the delta is not a great measure. Tape measures and callipers are reliable. Also note that when reliability is in question you have no external validity. For cost, tape measures and callipers win every time.

    I don't think these scales are accurate, even for a point of reference. I have lost nearly 30 lbs and 3 dress sizes, but according to the scale, my body fat % hasn't changed. I just don't pay any attention to that #. I go mostly by my tape measure and how my clothes fit.

  • Solar_Cat
    Solar_Cat Posts: 188 Member
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    There may be better BI scales than the one I have, but I know mine is absurdly inaccurate. The biggest influence on its reading is how wet my feet are. When they're dry, sometimes the scale doesn't even get a reading, and if it does, it's something ridiculous like 55%. When my feet are nice and wet, after a shower, it's much closer to what calipers tell me (21% - 22%), but even then the scale isn't consistent. One day it's 23%, next day it's 25%. And if I wait five minutes it's 30%. Nuts!
  • indianwin2001
    indianwin2001 Posts: 296 Member
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    JeffseekingV wrote: »
    Wheelhouse15 wrote: »
    JeffseekingV wrote: »
    I'm not rich so I can't afford to have multiple DEXA scans done at $150 a pop. I'd probably advocate ONE scan and then immediately do a bioimpedence scale, calipers, hand held bioimpedence etc... then compare the two for reference.

    It's not really the accuracy perse as long as it's consistent. If it's consistent, then the DELTA change in bodyfat is what is important.

    When the reliability of these scales is in question even the delta is not a great measure. Tape measures and callipers are reliable. Also note that when reliability is in question you have no external validity. For cost, tape measures and callipers win every time.

    They might not give an accurate absolute reading but as long as they are consistent in their error, that's fine with me.

    I've stepped on the scale like 3-4 times in a week and it showed about the same BF%

    Same with me--its trending downward. I had mine done with calipers at the gym and it was 18%. My scale for the last 2 weeks(I just got it) has been between 22 and 21% every day and it is trending down. I am getting it done at my gym with calipers Friday,so that will give me a better frame of reference.

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