What should you know about DEXA scans for body fat composition?

The scanner passes low-dose X-rays through the body and uses tissue differences to estimate bone mineral, lean tissue, and fat. Some reports divide the result by body region, which can help describe distribution rather than simply body weight.

DEXA is not a direct chemical analysis of body fat. Hydration, recent exercise, food intake, positioning, and the software used can affect comparisons. A single result cannot determine fitness, nutritional status, or disease by itself.

Follow the imaging centre's instructions. Tell staff about possible pregnancy, recent contrast studies, and metal or medical devices that may affect positioning. Ask whether they want you to avoid eating, strenuous exercise, or particular supplements before the appointment.

If tracking change, use the same centre and similar preparation each time. Discuss the report with a clinician who can consider waist measurement, blood pressure, glucose, activity, diet, medications, and goals. Avoid changing food intake or exercise sharply because of one scan.

Arrange a medical review for unexpected weight change, persistent tiredness, weakness, swelling, or concerns about restrictive eating. These symptoms need a broader assessment because a body-composition result does not explain their cause.

Get urgent help for fainting, severe breathlessness, chest pain, sudden weakness, or confusion. A DEXA appointment is not a substitute for assessment of acute symptoms.

Ask what the scan is intended to answer, which regions will be assessed, how reliable the comparison is, and what other measurements matter for your goal. Ask whether a follow-up scan would change your care.