Obesity affects one in three adults in the United States, according the Centers for Disease Control and Prevention. But your weight provides only one measurement of body fat. If you want to know accurately why your clothes don't fit or whether your muscle-enhancing workouts produced results, the water displacement test for body fat can help. The cost and effort required to analyze your body fat by the displacement method is substantial, though, which may make it more appealing to serious fitness buffs than to sedentary types.
How the Test Works
The water displacement method is based on the Greek philosopher Archimedes' principle of displacement. When you immerse yourself in water, fat distinguishes itself from muscle and bone because of its lower density level. Basically, fat is less dense than water, so it will cause you to weigh less underwater than an equal volume of muscle and bone would weigh. Getting an accurate reading from a water displacement test requires special equipment and trained professionals to read the results. You can't perform the test at home and few places offer the test.
Importance of Undertanding Body Fat Percentages
If you're overweight or clinically obese, it's important to get your weight under control. But you want to lose fat not muscle through diet and exercise. Weight loss, measured by a bathroom scale, measures only your overall weight. If you know your percentage of body fat before you embark on a weight loss regimen -- and continue to measure it -- you will know whether you are shedding unwanted fat or much-needed muscle. You could use this knowledge to alter the type of foods you eat or exercises you include in your workouts.
Other Fat-Measurement Methods
You can measure your body fat by methods other than the water displacement method. Other techniques include skin calipers; the body mass index calculations; air displacing; and dual X-ray absorptiometry. Skin calipers provide an easy means of measuring body fat. You measure skin flaps at various points on your body and use a mathematical formula to calculate body fat. Water displacement provides a higher degree of accuracy -- plus or minus 1.5 percent -- but skin calipers provide greater convenience that may encourage more frequent assessments.
Managing Your Weight
If you have recently undergone the water displacement test and received a bad result, then you will need to find out what you can do to get your fat level under control. Only 35 percent of adults in the U.S. take part in regular exercise sessions, according to the CDC. Regular exercise and a balanced diet can -- by any measure -- help you a healthy weight. If your clothes don't fit, you probably know the reason. You just need to get started on the solution.