Selected factors affecting the rate of reduction of body weight components during the first six months after bariatric surgery: A cohort study.

<b><br>Aim:</b> To determine whether the rate of slimming following bariatric surgery depends on the sex, type of bariatric surgery, time elapsed since surgery or body weight components.</br> <b><br>Materials and methods:</b> The material is comprised of the results of three series of anthropometric measurements in 91 obese patients (before bariatric surgery, about 3 months after bariatric surgery and about 6 months afterwards). The inclusion criteria were patients of Polish origin admitted to the hospital from July 1, 2017 to January 31, 2019 for surgical treatment of obesity and written consent for the surgery and participation in the study. The measurements included body weight components assessed by bioelectrical impedance analysis.</br> <b><br>Results:</b> The reduction of all features was greater after SG than GB (p<0.0001), greater in the first quartile than in the second quartile after surgery (p<0.0001), and higher for fat mass than for other body weight components (p<0.0001). The sex of the patients, type of bariatric surgery, time elapsed since the operation, and type of body weight component constituted interactive modifiers of the rate of reduction.</br> <b><br>Conclusion:</b> After bariatric surgery, the reduction of fat mass was quicker in men than in women. SG and RYGB lead to a greater reduction of fat mass than GB. Among all three analyzed procedures, only for SG did the rate of body weight component reduction not decrease in the second quartile after surgery. This finding should be taken into account when creating an algorithm for treating a patient after bariatric surgery</br&gt.