Protein Digestion After Bariatric Surgery in Older Adults

The goal of this clinical trial is to investigate protein digestibility after bariatric surgery. Does protein digestibility decrease after Roux-en-Y-Gastric Bypass? Does protein digestibility decrease after Sleeve Gastrectomy surgery? Does protein digestibility effect the ability to meet protein requirements?

Purpose of clinical trial is to investigate the digestion of dietary protein in older patients who have undergone Roux-and-Y Bypass (RYGB) or sleeve gastrectomy (SG) surgery. The primary objective is to compare dietary protein digestion during a test meal who have previously undergone a RYGB surgery, SG surgery, or control patients, using a dual stable-isotope method. The secondary objectives are to investigate the relationship between protein intake corrected for protein digestion and skeletal muscle mass, and to investigate the relationship between the rate of free amino acid appearance and protein digestion.