Good health involves more than just maintaining a healthy weight. Other factors, such as your body fat percentage, also play a role. According to Medline Plus, the recommended amount of body for men is between 17 percent and 19 percent. The recommended amount for women is 20 percent to 21 percent. Body fat percentage can be tested in numerous ways, and this measurement can then be used to guide you in choosing your fitness and nutrition goals.
Bioelectrical Impedance Analysis
When the bioelectrical impedance analysis method is used to measure body fat, electrodes are placed on your hands and feet. Because fat tissue contains less water than other tissues in your body, it will interfere with the progress of electrical impulses sent through these electrodes. The amount of interference is measured and used to calculate your body fat percentage. Your hydration level can greatly affect the accuracy of this type of body fat measurement so it is important that you avoid dehydrating substances such as caffeine and alcohol before the test. You should also avoid exercise for 12 hours before this type of measurement.
Underwater Weighing
To calculate your body fat percentage through the underwater weighing procedure, you are immersed in a tank of water and asked to exhale all water out of your lungs. From this process your body density is determined. Your body density measurement is then entered into an equation used to determine your percentage of body fat. While this method is typically considered very accurate, Nancy Clark, in her book "Nancy Clark's Sports Nutrition Guidebook," warns that this method is most accurate for those who fit a standard male profile. Because the equation used to determine body fat percentage is based on a standard male frame, this method can be inaccurate for women or very lean men.
Dual-Energy X-Ray Absorptiometry
The dual-energy X-ray absorptiometry, commonly called a DEXA scan, measures body fat by a full body X-ray. The X-ray differentiates between bone, fat and other body tissues, thereby providing body fat percentage and bone density. The DEXA scan is considered a highly accurate method of calculating body fat. However, this procedure can be quite expensive and difficult to obtain, as it is typically done in a hospital or research clinic.
Skinfold Testing
Measuring body fat percentage using the skinfold test involves a trained professional use calipers to measure adipose tissue in different locations on your body. Skin and adipose tissue are measured in each location and the measurements are entered into an equation, from which your body fat is calculated. Skinfold body fat tests can be done by using a three or seven site measurement. On men, three site measurements are done using the chest, abdomen and thigh or the chest, triceps and subscapular areas. Three site measurements for women are done using the triceps and suprailiac areas, along with either the thigh or abdominal area. The seven site measurement is done using the triceps, abdomen, suprailiac, thigh, chest, subscapular and midaxillary areas. Because more areas are tested, the seven site measurement is more accurate. The skinfold test for measurement is typically inexpensive and is often offered through fitness centers. Unfortunately, if the person administering the test is not experienced, this test can be more inaccurate than other forms of body fat testing.
References
- Medline Plus: Weight Management
- "Nancy Clark's Sports Nutrition Guidebook"; Nancy Clark, MS, RD; 2008
- "Health Fitness Instructor's Handbook"; Edward T. Howley, PhD; 1997
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