GIP and obesity due to melanocortin 4 receptor deficiency: In individuals who were metabolically healthy and with obesity (gastric banding = 8 or RYGB = 10), the MMT responses of plasma glucose, insulin, and c-peptide (to estimate hepatic insulin extraction; %HIE), incretins (GIP, aGLP-1), and PP were assessed 4–8 weeks prior to and following surgery.