Validity of Leg-to-Leg Bioelectrical Impedance Analysis to Estimate Body Fat in Obesity

Background Bioelectrical impedance analysis (BIA) is a safe and easy method of assessing body composition. Its accuracy to predict fat mass (FM) in obesity and the change in FM following weight loss is questioned. Our objective was to compare leg-to-leg BIA to dual-energy X-ray absorptiometry (DXA) in the assessment of FM in a large population, the changes in FM after Roux-en-Y gastric bypass (RYGB) and to estimate between-method differences (bias) and limits of agreement.