It has been reported that patients with severe obesity, with or without T2DM, present with significant and sustained weight loss with a consequent reduction in several mediators, some inflammatory, with elevations in adiponectin values in association with a decrease in leptin and tumor necrosis factor-alpha (TNF-α) levels after BS through Roux-en-Y gastric bypass (RYGB) [27,28]. This evidence concerns the gene LEP and obesity due to melanocortin 4 receptor deficiency.