Research

Hormonal

Roux-en-Y gastric bypass (RYGB) induces a progressive, adaptive rise in postprandial satiety hormones (PYY, GLP-1, enteroglucagon) and suppresses the compensatory rise in ghrelin, which explains the sustained weight loss and altered satiety without the typical counter-regulatory increase in appetite.

For individuals with morbid obesity, standard diet and exercise often fail long-term because the body increases hunger hormones (like ghrelin) to defend its higher weight. Roux-en-Y gastric bypass physically alters the gut to produce more satiety hormones (PYY, GLP-1) and suppresses hunger signals. This hormonal shift explains why patients feel fuller faster and stay full longer, leading to sustained weight loss without the typical rebound hunger seen in dieting. It is a physiological reset, not just a restriction.

ModerateSupportsMEDIUM confidence
Lack of the expected increase in appetite and food intake as components of a counter-regulatory response may be explained by gut adaptation and the consequent graded rise in the levels of gut hormones that promote satiety.
Cynthia-Michelle Borg et al. · British journal of surgery · 2006

Why this rating

Small sample size (n=6), prospective design, but robust hormonal measurements and clear statistical significance for hormone changes.

Source

Progressive rise in gut hormone levels after Roux-en-Y gastric bypass suggests gut adaptation and explains altered satiety

Cynthia-Michelle Borg et al. · British journal of surgery · 2006

DOI 10.1002/bjs.5227

cohort · n=6Cited 320×
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DOI resolved against Crossref · corpus check 2026-06-10

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