Digestive Hormones and Their Impact on Bariatric and Pharmacologic Weight-Loss Therapies

Obesity is a growing global health challenge associated with major cardiometabolic complications. While bariatric surgery remains the most effective treatment for severe obesity, recent advances in incretin-based pharmacotherapy, multi-receptor agonists, and endoscopic bariatric procedures have substantially expanded therapeutic options. Beyond mechanical restriction, these interventions exert their effects through complex hormonal and neurophysiological mechanisms involving gut-brain signaling, gastric motility, and enteroendocrine adaptations. Gut-derived hormones, including ghrelin, glucagon-like peptide-1 (GLP-1), peptide YY (PYY), amylin, and leptin, play a central role in the regulation of hunger, satiation, and satiety by integrating nutrient sensing, vagal afferent signaling, and central hypothalamic pathways. Surgical procedures such as laparoscopic sleeve gastrectomy and Roux-en-Y gastric bypass induce profound and durable hormonal remodeling, whereas endoscopic sleeve gastroplasty primarily modulates gastric physiology with more modest and heterogeneous endocrine effects. Intragastric balloons induce a transient delay in gastric emptying and achieve moderate short-term weight loss, although their metabolic and weight-loss effects appear limited in durability. In parallel, GLP-1 receptor agonists and emerging multi-agonist therapies reproduce several post-bariatric hormonal adaptations and achieve clinically meaningful weight loss. In this review, we summarize current knowledge on digestive hormone physiology and provide an updated overview of the hormonal mechanisms underlying pharmacologic, endoscopic, and surgical bariatric interventions, highlighting their respective roles within a continuum of obesity treatment strategies.