Being overweight or obese from an excessive amount of body fat leads to increased morbidity and mortality risks. This is well established through numerous findings and that your body weight alone is not always a good indicator for these risks. It's important to know your body composition; how much of your weight is due to body fat and how much of it is in the form of lean body mass.
The main contributor of excessive body fat is overeating. Research show that overeating can impair cognitive functions and impair memory. Mark P. Mattson of the Department of Neuroscience, Johns Hopkins University School of Medicine, recently published a paper giving an explanation on why overeating impairs cognition from an evolutionary perspective. Other laboratory studies explain the actual mechanisms at work in brain function impairment due to excessive body fat.
The amount of body fat is usually expressed in terms of a percentage of overall weight. Once you know your body fat percentage, you can refer to body fat charts and tables developed by health and fitness organizations to help you achieve a healthy body fat.
Although there are a number of different techniques that can accurately measure your percentage of body fat, they can be expensive and inconvenient. Using this online calculator together with a measuring tape or skinfold caliper, you can get a good estimate of your body fat percentage. Select from among the two types of measurement methods; a body circumference method developed by the U.S. Navy or body skinfold methods. Enter your measurements into the calculator. It will calculate your body fat percentage based on formulas developed for the selected measurement type.
Skinfold testing can predict body fat percentages within plus or minus 3.5 percent of your true body composition. Generally the more skinfold sites measured, the greater the accuracy. The accuracy of the U.S. Navy body circumference method is comparable to skinfold testing. However, both methods lose accuracy and are not very reliable for the obese or extremely lean individuals.
For body circumference measurements, use a measuring tape made of non stretchable material, preferably fiberglass. Measure your circumferences carefully with the same amount of tension at exactly the same spot each time you make a measurement. This will provide you with a consistent estimate on which to chart your progress.
The measuring tape should be applied so that it just makes contact with the skin and conforms to the body surface being measured. Don’t compress the underlying soft tissues. Make sure all measurements are made in the horizontal plane (parallel to the floor). All measurements, including height and weight, should be made while you are in thin underclothes and without shoes.
For skinfold measurements, please refer to your skinfold caliper manual for instructions. As a general rule, skinfold measurements should always be taken from the same side of the body, usually the right side. Take a minimum of two measurements at each skinfold site. If the two measurements differ by more than 2 mm, take a 3rd. Record the average for the site.
U.S. Navy Body Circumference Method
Neck, waist and hip circumference measurements are taken differently for men and woman. The formula does not require hip measurements for men. Waist measurements are taken at the belly button for men, and above the belly button for women.
For males, measure your neck circumference at a point just below the larynx (Adam’s apple). Don’t place the tape measure over the Adam’s apple. You should look straight ahead during the measurement, with shoulders down (not hunched). Keep the tape as close to horizontal as anatomically feasible. Measure waist circumference against the skin at the belly button level and parallel to the floor. Keep arms at the sides.
For females, the neck measurement is taken the same way as taken for males. Measure waist (abdomen) circumference against the skin at the skinniest part of the waist. This is usually about halfway between the navel and the end of the sternum (breastbone). Ensure that the tape is level and parallel to the floor. Keep arms at the side. Hip measurements should be taken by placing the tape around the hips so that it passes over the greatest protrusion of the buttocks as viewed from the side. Ensure the tape is level and parallel to floor. Apply sufficient tension on tape to minimize effect of any clothing.
Jackson-Pollock 3-Site Skinfold Method
This is a simple method that you can perform yourself. It is fairly accurate for most people with an average build. However, it tends to underestimate body fat for athletes, body builders or very lean individuals. The skinfold measurement sites differ for men and women. The formula uses the chest, abdomen and thigh for males; the tricep, suprailiac and thigh for women.
Jackson-Pollock 4-Site Skinfold Method
With this method, the skinfold measurement sites are the same for both males and females. Four sites are used which makes this method slightly more reliable than the 3 site method but again, it loses accuracy for very lean individuals.
Jackson-Pollock 7-Site Skinfold Method
This method produces the most reliable results of the three Jackson-Pollock series of skinfold measurements. The test uses seven skinfold sites the locations of which are the same for both males and females.
Durnin-Womersley Skinfold Method
The Durnin-Womersley method is probably the most popular skinfold measurement methods used but it tends to overestimate body fat for very fit individuals. It utilizes four skinfold measurements at the same four skinfold sites for both males and females.
About Body Fat Bathroom Scales
Besides measuring your weight, modern bathroom scales can now determine your body composition. However, their ability to gauge body fat percentages can be considered poor compared to skinfold testing or circumference measurement methods. These scales send electric currents through your body when you step barefoot on the metal foot pads. Fat and muscle have different resistances to these currents. Based on these resistance variances, the scales use an algorithm to compute an estimate of what percentage of your weight consists of fat.
A few years back, Consumer Reports tested 6 bathroom scales that gave body fat readings in addition to weight. Price ranged from $40 to $150. Consumer Reports found that the readings were off by more than 20%. Bathroom scale technology may have advanced since then but their accuracy could still be called into question. The scales gave consistent readings at least, so they still may be useful as a tracker of relative gains and losses of body fat over time.
Use a good quality scale to track your progress on a regular basis and occasionally check your body fat using the circumference or skinfold methods as described earlier. Note the difference between what the scale says and the result you get from either of the two other methods. Keep that difference in mind when using the scale and apply that difference (add or subtract to/from) the scale reading to get a more accurate indication of your actual body fat percentage.