From the Guidelines
The best way to determine your body fat percentage is through dual-energy X-ray absorptiometry (DEXA) scanning. This method is considered one of the "gold standards" for body fat assessment, as it provides a high degree of accuracy and precision in differentiating between lean and fat tissues 1. DEXA scanning uses low-dose X-rays to measure body fat percentage, and its results have been validated against other methods, such as the 4-compartment model, which estimates body fat from measurements of body density, total-body water, and bone mineral values.
Some of the key benefits of DEXA scanning include:
- High accuracy and precision in measuring body fat percentage
- Low radiation exposure (1Sv), making it suitable for repeated measures in a clinical setting
- Quick and easy to apply, with results available immediately
- Ability to assess regional body fat distribution, including abdominal fat mass
While other methods, such as hydrostatic weighing and air displacement plethysmography, can also provide accurate measurements of body fat percentage, DEXA scanning is generally considered the most reliable and precise method 1. Bioelectrical impedance analysis (BIA) scales and handheld devices can provide reasonable estimates, but their accuracy can be affected by factors such as hydration levels and recent exercise. Skinfold calipers can also provide fairly accurate results when used by a trained professional, but may not be as precise as DEXA scanning.
Overall, DEXA scanning is the recommended method for determining body fat percentage, due to its high accuracy, precision, and reliability, as well as its ability to assess regional body fat distribution 1.
From the Research
Methods for Determining Body Fat Percentage
- Dual-energy X-ray absorptiometry (DXA) is a widely used technique for estimating body fat percentage, as it provides accurate measurements of fat mass and lean mass 2, 3, 4, 5.
- DXA measures the attenuation of X-rays at two different energies to calculate bone mineral content and soft tissue composition in the scanned region 5.
- The technique is considered safe and simple, with a very low radiation dose, making it suitable for children and the old and frail 5.
Accuracy and Limitations of DXA
- DXA measurements have excellent precision, but accuracy can be problematic due to differences in calibration, bone edge detection, and other factors between commercial systems 5.
- Systematic differences in bone and soft tissue values are found between different DXA systems, which can lead to variations in estimated body fat percentage 5.
- DXA is not considered a "gold standard" for body composition, but its performance is improving with ongoing development and new software 5.
Alternative Methods for Assessing Body Composition
- Skinfold thickness and waist circumference are field-based assessments that can provide a cost-effective alternative to DXA for determining body composition in athletic populations 6.
- However, existing anthropometric equations developed in able-bodied populations may substantially underestimate body fat content in wheelchair athletes, particularly non-walkers 6.
- Impairment-specific equations may be needed for accurate assessment of body composition in wheelchair athletes 6.
Reference Values for Body Fat Measures
- Reference values for DXA-derived fat mass measurements are necessary for interpretation and accurate classification of individuals at risk for obesity-related health complications 3.
- Normative reference values for fat mass variables from DXA measurements are available for Caucasian adults, providing a resource for clinicians and researchers 3.