8,153
edits
Changes
no edit summary
This is a comparison of the ways that body fat can be measured. None of the approaches is perfect, but they can be useful.
==Skinfold Calipers==
These are cheap ([http://www.amazon.com/gp/product/B000G7YW74 $6]), but tricky to use accurately. Slight I have several of these calipers and each one requires different pressure to 'click' and record the skinfold. This difference in pressure can make a big difference in the skinfold measurement. Also, slight changes in location of the measurement can make a big difference to the reading, so practice is required to get the same spot each time. With lower levels of body fat, the resolution of the calipers can also be is a problem. The calipers only measure the fat under the skin, and at a few locations. There is significant person to person variation in fat distribution through the body, limiting the accuracy even with expert usage. The two big advantages of calipers are that they are cheap, and they measure the body fat directly.
http://ecx.images-amazon.com/images/I/31c6Xo-ic3L._SS500_.jpg
==Body Fat Scales==
These Bioelectrical Impedance Analysis (BIA) scales use an imperceptible electrical signal to calculate the amount of water in the body. From this Total Body Water (TBW), it is possible to estimate body fat. This makes these scales quick and easy to use, but there their accuracy is limitedquite poor. The level of hydration has a significant impact on the reading, so readings need to be taken at the same time of day with the same level of hydration. The [[Book Review - The 4 Hour Body|4 Hour Body]] recommend drinking 1.5 liters (3 pints) of water, waiting 30 minutes, urinating and then taking a measurement. The biggest problem for an athlete is that BIA is particularly inaccurate when fat free mass, including glycogen, changes<ref name="BIA1"/><ref name="BIA2"/>. I've noticed that the day after a long run, the scales claim a much larger loss of body fat than is reasonable. I categorize these scales into three types.
===Lower Body Only===
Most body fat scales have electrodes only on the feet, so the electric current only goes from one foot to the other. This only measures the lower part of the body, not the whole body. I have the Tanita BF680 which retails for [http://www.amazon.com/Tanita-BF680-Scale-Monitor-Athletic/dp/B000094ZGH $60].
===Abdominal Muscle Definition===
If your body fat is low enough, the definition in your abdominal muscles (six pack) can be used to monitor body fat changes. There is no specific body fat percentage for having a six-pack, but the common thought is that you need to be 12-8% for men and 18-14 for women.
==References==
<references>
<ref name="BIA1">Body composition changes assessed by bioelectrical impedance measurements http://www.ncbi.nlm.nih.gov/pubmed/2923071</ref>
<ref name="BIA2">Changes in fat-free mass during weight loss measured by bioelectrical impedance and by densitometry http://www.ncbi.nlm.nih.gov/pubmed/2912008</ref>
</references>