- Over the last years increasing evidence suggests that the beneficial effects of bariatric operations might be related to the suppression of appetite caused by the release of the anorectic gut hormones such as peptide-YY (PYY) and glucagon-like peptide-1 (GLP-1)by the L cells of the distal gut and the suppression of the orexigenic hormone ghrelin released by the stomach.Obese people have a blunted rise in PYY and GLP-1 after a meal, possibly resulting in impaired satiety and hence greater food intake.