What is body composition?

Body composition is the proportion of a human's body fat to lean body mass. Body fat is all of the fat in the body, including lipids and nonessential fats such as fat cells and fat tissues. Lean mass, or lean tissue,is everything in the body that is not fat, including bones, organs, muscles, tissues, and water. Body composition is expressed as a percentage of body fat and a percentage of lean mass. Measuring body composition using one of several methods can help individuals calculate their body fat percentage.

Impact of Body Composition on Overall Health

Body composition can impact an individual's overall health. While body fat is necessary for certain body functions, such as providing energy, regulating hormones, and assisting in protecting internal organs, excessive body fat can be detrimental to an individual's health. Too much body fat can increase a person's risk of developing certain diseases, including cancer, heart disease, and diabetes. Furthermore, excessive body fat can make moving more difficult and impact an individual's appearance. People who are overweight or obese generally have more body fat than people who are physically active or thin. Having too little body fat can also negatively affect a person's health and lead to a compromised immune system, hair loss, anemia, and more.

Body Fat Percentage

The American Council on Exercise (ACE) recommends specific body fat guidelines for both men and women of all levels of activity. ACE is a nonprofit organization that provides health and fitness information as well as educates and certifies professionals in the fitness industry. Following are the ACE body fat percentages for men:

• Physically active individuals: 2 percent to 17 percent




• Athletes: 6 percent to 13 percent




• Obese individuals: more than 25 percent

Following are the ACE body fat percentages for women:

• Physically active individuals: 10 to 24 percent




• Athletes: 14 percent to 20 percent




• Obese individuals: more than 32 percent

Methods for Measuring Body Composition

Measuring body composition enables individuals to determine whether they should lose or add body fat. They can use this information to develop a plan that includes a healthy diet and exercise to help them reach their goals. Body composition can be measured using several different tools, however, not all of these methods are accurate. Additionally, some of these methods are expensive and not readily offered.

Skinfold calipers measure body composition quickly and easily. The calipers are applied to folds of skin on an individual's body, and the thickness of the skin—along with the fat directly under the skin—is measured. Typically, four to six different areas of the body are measured, including the abdomen, sides of the waistline (commonly referred to as love handles), triceps, shoulder blades, and calves. The sum of the skinfolds is calculated, and this calculation is referenced against data to determine the individual's body fat percentage. Although skinfold calipers are fairly accurate, they may not be as accurate when used on people with body fat deposits.

A bioimpedance measuring device is another fast and easy tool to use for measuring body composition. The device, which is either a scale or a handheld tool, sends a small electrical current through a portion of the individual's body. The current is then used to measure the person's body fat percentage. Like skinfold calipers, bioimpedance measuring devices may not be accurate with individuals who have fat deposits. Furthermore, hydration and skin temperature usually influence readings.

One of the most accurate body composition measuring devices is the DEXA scan. With this method, low-dose radiation and X-rays are used to measure fat in the person's body. By using a DEXA scan, fat can easily be distinguished from both muscle and bone. While the DEXA scan provides accurate results, it is expensive and not readily available.

Whole body plethysmography, also called BOD POD, is another accurate method used to measure body composition. A pod that resembles an egg measures the volume of air that a person displaces. This enables the pod to measure the individual's overall density. The person's body fat percentage is then calculated. Like the DEXA scan, whole body plethysmography is not always used because of its cost and availability.

Another body composition measuring method is underwater/hydrostatic weighing. This highly accurate method uses water to measure body composition. A person sits on a scale submerged in water, and the scale measures the volume of water that the individual displaces. It also calculates the person's overall density. From there, the person's body fat percentage is calculated. Underwater/hydrostatic weighing is also expensive and not always offered.

While all of these methods are good ways to measure body composition, not all body measuring methods can calculate body composition. For example, a typical bathroom scale cannot measure body composition because it is unable to distinguish between body fat and lean body mass. A scale only measures an individual's total weight. Additionally, body mass index (BMI) cannot be used as a tool to measure body composition. BMI is used to calculate the ratio of an individual's weight to height. As with a scale, BMI cannot distinguish between body fat and lean body mass.

Bibliography

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"5 Ways to Test Your Body Composition." Active. Active Network, LLC. Web. 28 Jan. 2015. http://www.active.com/fitness/articles/5-ways-to-test-your-body-composition

"Message from Our President." American Council on Exercise. American Council on Exercise. Aug. 2014. Web. 28 Jan. 2015. http://www.acefitness.org/about-ace/our-team/default.aspx

Reese, Meghan A.T.B. " Underweight: A Heavy Concern." Today's Dietitian. Great Valley Publishing Company, Inc. 2008 Jan. Web. 29 Jan. 2015. http://www.todaysdietitian.com/newarchives/tdjan2008pg56.shtml

Scott, Jennifer R. "What Is Body Composition?" About Health. About.com. 18 Dec. 2014. Web. 28 Jan. 2015. http://weightloss.about.com/od/backtobasics/f/bodycomp.htm