Oct 17, 2026
Most people step onto a scale, see a number, and assume it tells them something meaningful about their health. It tells them how much they weigh. It does not tell them how much of that weight is fat, how much is lean tissue, or where the fat is stored.
That is why body-composition testing has become popular. Among the available methods, dual-energy X-ray absorptiometryā€”usually called DXA or DEXAā€”is particularly useful. But there is a distinction to understand before you become too attached to a body-fat percentage printed on a report:
DEXA is a good measurement tool. It is not a perfect measurement of biological truth.
DEXA uses two X-ray energies that are attenuated differently as they pass through tissue. Software analyzes those signals to estimate three main compartments: bone mineral content, fat mass, and lean soft tissue. A whole-body scan can also divide the results into regions such as the arms, legs, and trunk. The test is relatively...
