GCG and obesity due to melanocortin 4 receptor deficiency: ESG significantly delayed gastric emptying compared to LS at 3 and 12 months; greater delay in GE at 3 months correlated with greater weight loss. Gastric motility was preserved. Fasting ghrelin, GLP-1, and PYY increased after ESG. ESG promotes weight loss via delayed gastric emptying and hormonal changes while preserving motility, supporting its clinical adoption for obesity management