GLP1R and obesity due to melanocortin 4 receptor deficiency: In this Review, we discuss similar preclinical studies that present novel concepts in the neural control of food intake and body weight, with reference to endogenous GLP-1, GLP-1R agonists, and bariatric surgeries like Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG), which remain the most effective treatments for severe obesity [9].