Body fat is a good, reliable indicator of fitness and health. When body fat percentage is high, it increases the risk of developing serious health problems such as heart disease and diabetes. A healthy body fat percentage range for men is 14 to 20 percent and 17 to 24 percent for women. Several calculation methods are available to determine body fat percentage; these calculation methods vary according to the specific measurement technique being used.
Skinfold Testing
Skinfold testing is one of the easiest and most inexpensive methods of body fat testing and calculation, therefore it is done more commonly than are other testing methods. Calipers are used to measure the thickness of skin at specified body locations under the assumption that the fat located just under the skin reflects a proportion of total body fat. Skinfold thickness is measured at the triceps, chest, abdomen, thigh and hip area. Skinfold, or anthropometric, measurements are used in a complex regression equation to predict body fat composition. The standard equation is body fat percentage equals 495 divided by body density minus 450 times 100.
Other Measurment Methods
Underwater weighing, or hydrodensitometry weighing, is the laboratory standard for body fat calculations and assumes that the density of both fat mass and fat-free mass are constant. This method, however, is quite difficult to complete accurately, making it a less-feasible option for body fat calculations in everyday use. Duel Energy X-ray Absorptiometry, DEXA, scanning provides a high degree of precision and is a reliable measure of body fat determination. This method is quickly surpassing underwater weighing as the laboratory standard.
Factors
When calculating body fat percentage in men and women, different factors must be considered. In women, total body weight in combination with wrist measurement, waist measurement, hip and forearm measurements are used. For men, only total body weight and waist measurements are used. Measurements and body weight are most accurate when taken after waking from seven to eight hours of sleep.
Calculation
One easy to use body fat calculation for women involves first calculating lean body mass. This is done in several steps, first by multiplying total body weight by 0.732 and adding the product to 8.987. Second, divide the wrist measurement by 3.140 followed by multiplying the waist measurement by 0.157. Hip measurements should be multiplied by 0.249 and forearm measurement multiplied by 0.434. Body weight calculation is added to the wrist calculation, waist calculation is then subtracted and hip calculation is subtracted, with forearm measurement added at the end to equal lean body mass. Lean body mass is then subtracted from total body weight to determine body fat weight. Body fat percentage is then determined by multiplying body fat weight times 100 divided by total body weight. In men, the process is simpler. Total body weight is multiplied by 1.08 added to 94.42, and the waist measurement is multiplied by 4.15. Waist measurement is then subtracted from totally body weight calculation to determine lean body mass. The lean body mass is then subtracted from total body weight to equal body fat weight. Body fat percentage is then determined by multiplying body fat weight by 100 and dividing by total body weight.
Member Comments