Research

Hormonal

Roux-en-Y gastric bypass (RYGBP) surgery induces an exaggerated postprandial secretion of Peptide YY (PYY) and suppresses fasting bioactive (octanoylated) ghrelin levels, mechanisms that contribute to sustained weight loss and maintenance by promoting early satiety and reducing hunger.

For individuals with morbid obesity, Roux-en-Y gastric bypass surgery alters gut hormones to favor weight loss maintenance. Specifically, it triggers a strong release of Peptide YY (PYY) after eating, which signals fullness to the brain, and lowers active ghrelin (the hunger hormone). This hormonal shift helps patients feel full sooner and stay full longer, making it easier to maintain weight loss compared to dieting alone.

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In summary, the absence of a compensatory increase in ghrelin concentrations that usually occurs with diet-induced weight loss, and the exaggerated postprandial PYY response after RYGBP, may contribute to weight loss and to the ability of an individual to maintain weight loss after this surgical procedure.
Judith Körner et al. · The Journal of Clinical Endocrinology & Metabolism · 2005

Why this rating

Randomized controlled comparison with matched controls, though sample size is modest (n=32).

Source

Effects of Roux-en-Y Gastric Bypass Surgery on Fasting and Postprandial Concentrations of Plasma Ghrelin, Peptide YY, and Insulin

Judith Körner et al. · The Journal of Clinical Endocrinology & Metabolism · 2005

DOI 10.1210/jc.2004-1076

cross_sectional · n=32Cited 419×
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DOI resolved against Crossref · corpus check 2026-06-10

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