DEXA Body Composition Scans Compared

DEXA scans are considered the gold standard for body composition with 1-2% margin of error for body fat percentage. They're more accurate than bioelectrical impedance scales (3-5% error) or calipers. DEXA provides regional body fat distribution and can track visceral fat specifically.

For tracking body composition changes, every 3-6 months is ideal. This allows enough time for meaningful changes in lean mass or fat mass. More frequent scanning (monthly) may show too much noise from hydration and glycogen fluctuations.

DEXA scans use very low radiation - about 0.4 mSv per scan, roughly equivalent to a few hours of natural background radiation or a cross-country flight. This is 10-20x less radiation than a chest X-ray. Annual or quarterly scans pose negligible health risk.

DEXA uses X-ray technology and is the gold standard (1-2% accuracy). InBody uses bioelectrical impedance and is less accurate (3-5% error) but faster, cheaper, and widely available at gyms. DEXA is better for baseline measurements and tracking progress, while InBody works for quick spot-checks.

For best accuracy:avoid eating 2-4 hours before, avoid exercise the morning of, stay well hydrated (but empty bladder before scan), wear minimal clothing without metal, and try to scan at the same time of day for tracking purposes.

DEXA provides:total body fat percentage, lean muscle mass, bone mineral density, regional breakdown (arms, legs, trunk), visceral fat area/volume, and android/gynoid fat ratio. Some facilities add RMR (resting metabolic rate) testing to estimate calorie needs.