How a Body Fat Tester Works

Body fat testing is a method of determining how healthy a person is, as lower body fat levels correlate with good overall health. There are several methods of testing body fat, and they work with varying degrees of accuracy.

Measurement

• Body fat can be measured with underwater weighing, where body density is calculated with body volume. The person is weighed outside of the tank, submerged, brought out of the water and weighed again. Fat is not as dense as water. In water, those with more body fat will weigh less than those with more bone and muscle. Another method uses body fat calipers. Calipers are clipped to fatty sites such as the tricep, thigh and waist. The fat pinched is measured in inches, and the fat just under the skin represents total body fat.

Comparison

• When using the caliper method, the inches of fat held between the caliper prongs are measured against a chart, and each measurement correlates to a specific body fat percentage. The water testing method is the most accurate, but is often expensive and inconvenient.

Weaknesses

• One must consider their height, weight, lean body mass and ethnicity when determining the right body fat percentage, as the same measurement methods may not work equally for all people. Unless you take the water test, you will get a measurement that is within 2 to 3 percent accurate. This small percentage makes an incredible difference in appearance, so it is best to use caliper measurements to chart progress rather than obtain an accurate measurement.