Herein, we present a 1-year longitudinal evaluation using continuous glucose monitoring (CGM), bioelectrical impedance analysis (BIA), and computed tomography (CT) fat scans after LSG/DJB in a patient with obesity and T2DM.<h4>Case presentation</h4>Our patient was a 33-year-old female with obesity and T2DM who had been treated with intensive insulin therapy (50 units/d) before LSG/DJB. This evidence concerns the gene INS and obesity due to melanocortin 4 receptor deficiency.