What’s in a Body fat test? by Linda Cusmano

Something that many obsess over is body fat.  To strive for the most accuracy in order to know your exact body fat has been a difficult journey.  Exercise enthusiasts at a recreational level are much keener to know these figures than a few years ago.  At one point this was something mainly used by elite athletes and physique competitors done by skin fold testing using calipers or for those with access, hydrostatic weighing.

Once known to be THE most accurate form of body fat testing it fell under scrutiny a few years back and the accuracy of this test was questioned. 

Hydrostatic weighing is done by complete submersion of the individual after they have exhaled all they can.  Of course dry weight is measured first with the participant in as little clothing as possible.  Then they are submerged and this will give a density for the person.  With that figure the body fat percentage is calculated.  This is still known as most accurate compared to other means but realistically skin fold calipers are second best for accuracy when looking at digital machines which are hand held.
Skin fold caliper accuracy is dependant on a few factors.  First is how experienced the tester is.  It is crucial that the sites are found accurately and taken in the same spot each time.  The next factor is the type of caliper used and its condition.  The Accu-measure and Slim Guide which are plastic ones and most common plus affordable but can warp from heat and are not as accurate as the Harpenden, Lafayette and Lang.  The formulas used will also determine accuracy.  Timing of the test must also be followed along with the other pre testing criteria.  The Jackson-Pollock formula is one of the fastest and commonly used.
Most gyms will have an Omron which is hand held and can vary in accuracy depending on how its held.  This is probably the least accurate but because these tests are not meant as a end all, be all figure, but mainly used for comparison and to show change, they suffice.  The Tanita brand has a few choices from the small and simple scale you stand on which is sold for home use to the larger sized scale version, is a great middle of the line model.  They have a few models which have a better accuracy than the hand held.  The prices for these have also become more realistic because of the popularity and demand.
There is a higher end model in both cost and accuracy which is sold by Bioanalogics called the ELG or Electrolipograph.  A current is between electrodes on the hands and feet, in specific locations, that is measured by the currents’ speed through your body water and fats.  A bio impedance reading is given and with some calculation software combined with your anthropometric measurements, you get a body fat percentage.  This is known to be the 2nd accurate next to hydrostatic and is portable but a few thousand dollars.

Regardless of how you determine your body fat, the key thing to remember is that this figure is to be used with your weight, height, measurements and combined to track changes over time.  Getting stuck on a percentage of body fat is not a healthy way to think and will probably frustrate you more than help you.  This can be as encompassing as body weight, another reading meant to be used for tracking only.  The fact that we are made up of water, muscle, fat and bones means that unless it is all sorted into piles and put on a scale you simply cannot get a fully accurate figure.  You have to think about why you want this figure and it’s purpose.  Unless you are an athlete or medically need to know this for health reasons then it should not be a huge concern and need be taken with a grain of salt! 

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