Calculating your Body Fat Percentage

Calculating your body fat percentage is remarkably easy if you have a home tape measure that has both centimeters and inches. Just a few simple measurements, using the centimeter side of the tape measure (centimeters gives greater precision to the measurement), entering those numbers into an on-line body fat calculator, and you are done.  The standard measure used by most people is called the “U.S. Navy Circumference Method.

A note of caution when doing your measurements:  do each measurement three times and average out the scores.  You will get more accurate numbers and therefore more accurate results.

The first measurement is to determine how tall you are without shoes.  You can measure yourself at home by standing straight, with your back against a wall, and having someone place a book flat on your head.  Mark that spot on the wall.  Use your tape measure to determine your height.  Or just use the number you were given from the last time your height was measured. (We tend to shrink as we age.)

Second, measure your neck just below the voice box (larynx).  It’s best to have a slight downward slant from the back of the neck to just under your voice box.

Third, measure yourself at the waist.  Men should measure themselves at the navel (or belly button) and women should measure themselves at the smallest part of the waistline.

Last, women should measure themselves at the largest part of their hips.  (This measurement is not necessary for men.)  Enter all these numbers into the appropriate boxes, click the “calculate” button and your body fat percentage will appear.

If you want to have a body fat calculator available on your home computer, you can purchase a program from Diet Power called “Body Tracker.”  In this program you have several ways to calculate your body fat percentage.  The first is a general set of measurements which includes: hip, waist, bicep, thigh, calf, neck and chest, in inches.  A second page provides you with five sets of calculations using millimeters and one calculation using inches. First is the Jackson/Pollock 7-site measurement including:  chest, abdominal, thigh, tricep, subscapular, Suprailiac, and midaxillary.  The second is also a Jackson/Pollock calculation using only 4 sites: abdominal, thigh, tricep, and Suprailiac.  The Jackson/Pollock 3 uses three sites:  tricep, Suprailiac, and thigh.  The fourth calculation is the Pasrrillo 9-site measurement:  chest, abdominal, thigh, bicep, tricep, subscapular, Suprailiac, lower back, and calf.  The fifth calculation is the Durin/Womersley with 4 measurement sites:  bicep, tricep, suprailiac, subscapular.  The last set of calculations is in inches: height, waist, neck, hips. This is the Navy’s method.  For someone who wants a more precise definition of body fat, using all five of these methods and comparing the results with one another should indicate the differences in the calculations.  If taking fewer measurement sites will give you the same calculation as taking more measurements, then, by all means, use the one with the fewer measurement sites.

For those who just want a general idea of how much fat they are carrying, the Navy method is the simplest and easiest to use as it accepts both inches as well as centimeters and has fewer measurement sites.

Another common method of estimating body fat percentage is the Body Mass Index or BMI which uses only two measurements:  height and weight.  The problem with BMI is that it does not indicate actual body fat, it only specifies weight.  A heavy body building man may weigh the same as a heavy sedentary man but the body builder’s weight is muscle whereas the sedentary man’s weight is fat.  BMI does not discriminate where the weight comes from.

Another common body fat measurement is skin fold thickness with the use of measurement calipers. This is a method commonly used in gyms.  This measurement assumes that the individual is not old and has not recently lost a great deal of weight.  With age, and with great weight loss, the skin sags.  Skin fold calipers cannot discriminate what is subcutaneous fat from sagging, aging skin.  Some people also object to this method as the person doing the testing must literally pinch the skin in order to measure it and that hurts.  Some people bruise easily and skin fold testing will cause bruising where tested.  Also, the measurements may differ depending upon the person doing the measurements.

Impedance Machines are becoming more common and some varieties are seen in drug stores.  These are bioelectrical machines to measure fat content.  Their accuracy is questionable.  Use the Navy method to estimate your body fat, then try out the Impedance machine in the drug store and see how well they agree.

Another method of calculating body fat includes the use of Underwater weighing (hydrostatic weighing), which requires a good laboratory set up.  Body weight is measured underwater, requiring subjects to hold their breaths and not move long enough to get a reading.   This is not an appealing procedure for many people.  It may, however, be the most accurate.

Once you know how much body fat you have, how do you know if it is unhealthy or not?  As a general rule, anything over 25% body fat for men is considered “too fat” whereas anything over 32% body fat is “too fat” for women.  In this case “too fat” refers to the fact that when men and women exceed their “healthy” body fat limits they put themselves at risk for developing major diseases.  These, however, are just general guidelines.  Healthy weight ranges for adults have been established for both gender and age and are easily found on the internet. It is as unhealthy to go below the minimums as it is to go above.

For most people, using the on-line navy method is the quickest, easiest and cheapest method of estimating body fat.


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