Fat mass to fat-free mass (FM/FFM) ratio was categorized into 3 groups: Group 1, normal, <0.40; Group 2, obese and increase of FM is small relative to that in FFM, 0.40 to 0.80; and Group 3, SO, >0.80.
REE (by indirect calorimetry) and body composition (fat-free mass or FFM, fat mass or FM by bioelectrical impedance analysis) were determined before and after 12 months in 154 patients with obesity treated with laparoscopic sleeve gastrectomy (LSG).
The accuracy of body composition assessment using BIA decreases with increasing obesity, and its reliability to track changes is reduced with high initial or variations of body weight, FM, FFM and BMI.