1. FAT: How is it measured?
Description
This article is from the Fitness FAQ, by Jeff Gleixner (glex@cray.com) with numerous contributions by others.
1. FAT: How is it measured?
Body FAT (BF) is usually given as a percentage of total weight. If a
100lb person has 10% body FAT, that person has 10lbs of FAT and 90
pounds of lean body mass (LBM) (water, muscle, bone, etc). There
are 3500 calories in 1 pound of FAT.
Body FAT is usually tested in 4 different ways.
Hydrostatic weighing (Immersion): Weight is taken while under the
water and it is used to find your %BF.
Pros: Thought to be the most reliable.
Cons: A lot of equipment is needed, usually found at most
Universities. Time consuming and sort of a hassle.
What you eat the day before, or before the test,
can affect the accuracy.
Infrared: Infrared light is used to determine your body FAT.
Pros: Fast.
Cons: Not very reliable.
Impedance: The %BF is calculated by measuring the impedance between
certain areas of the body, usually between the fingers
and the toes.
Pros: Fast.
Cons: Not very reliable.
Pinch test: Calipers are used to measure skin fold thickness.
Pros: Thought to be very reliable. The more places tested
the more accurate the results. Most gyms have a
caliper.
Cons: May be embarrassing to have someone pinch your FAT.
If the person is inexperienced the results may be
very inaccurate.
From the Weights mailing list:
From: Steven Heston <heston@homey.som.yale.edu>
Subject: Easy bodyfat measure
Here is a simple formula for estimating your bodyfat
(in pounds). I think it was published in the a book with
a title like _The YMCA Guide to Physical Fitness Assessment_.
For men: Bodyfat = -98.42 + 4.15*waist - .082*bodyweight,
For women: Bodyfat = -76.76 + 4.15*waist - .082*bodyweight,
where "waist" is your waist measurement in inches, and
"bodyweight" is your total body weight in pounds. Divide
your bodyfat by your total weight to get your bodyfat
percentage.
Regardless of which test you use, record the %BF and have it tested
after a few months, using the same method and person, if possible,
to make sure what you're doing is having the right effect. If
involved in resistance training your weight should go up or stay the
same while your BF goes down. (An increase in LBM is a GOOD thing).
For men < 15% is considered athletic, 25 being about average.
For women < 22% is considered athletic, 30 being about average.
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