Body fat analyzers: How accurate are they?

Date Updated: 07/08/2020

Answer Section

Although the technology is improving, it's hard to get an accurate body fat measurement from most available commercial body fat analyzers.

Various types of body fat analyzers — also called impedance meters — are available to the general public. Results from portable body fat analyzers can vary, though. Your body fat measurement can depend on many factors such as the device's quality and how hydrated you are when you have the measurement.

If you're concerned about your body fat percentage, you may want to skip the commercially available body fat analyzers. Ask your doctor about the use of more-accurate measurement techniques.

Depending on the circumstances, options may include:

Dual energy X-ray absorptiometry (DXA). DXA is a specialized X-ray exam. It provides detailed information about the ratio between fat, muscle and bones in specific parts of your body.
Air displacement plethysmography. With this technique, you're enclosed in a computerized, egg-shaped chamber (Bod Pod, others). The device measures your weight and volume to determine your body density. Then it uses these figures to calculate your body fat percentage.
Underwater weighing. This method involves first being weighed on dry land and then while sitting on a special chair lowered under water. Your weight measurements on land and underwater are then used to determine your body density and calculate your body fat percentage.

Body fat can also be estimated using cross-sectional imaging methods such as magnetic resonance imaging (MRI), nuclear magnetic resonance spectroscopy and computerized tomography (CT).

These scans can provide the most precise body composition measurements, especially for intra-abdominal fat measurement. But they're expensive and aren't usually used only for measuring body fat. Imaging tests such as ultrasound may also be used to measure body composition.

Researchers continue to study other methods to assess body fat.

Depending on the information desired, you and your doctor can determine the most appropriate type of body fat measurement. Keep in mind that specific body fat measurement techniques can be expensive and may not be available in all locations.