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Study breakdown

Roux-en-Y Gastric Bypass Produces Higher GLP-1 Spike Than One-Anastomosis Bypass After Meals

RPEP-152812026Heinonen, S; Karppinen, J E; Saarinen, T; Groop, P-H; Juuti, A; Holst, J J; Pietiläinen, K H
evidence
The takeaway

RYGB produced 31% higher early-phase GLP-1 response and 32% higher peak GLP-1 vs OAGB despite similar weight loss, correlating with greater postprandial hunger reduction.

31% higher early GLP-1

RYGB produces a faster, larger GLP-1 spike after meals than one-anastomosis bypass, explaining its greater hunger suppression

What the researchers found

RYGB vs OAGB: early-phase GLP-1 AUC 31% higher at 6 months (p=0.030); peak GLP-1 ~32% higher (p<0.05); total GLP-1 AUC increase: RYGB 330% vs OAGB 259%; greater hunger reduction with RYGB; similar weight loss (~25%).

Why it matters

Understanding how different surgeries affect gut peptide responses informs surgical technique selection and helps develop drug therapies that mimic the most effective peptide profiles.

How the study worked

41 participants from randomized RYSA trial (21 RYGB, 20 OAGB), 360-min mixed-meal tests at baseline, 6, and 12 months, measuring GLP-1, secretin, glucose, insulin, C-peptide, and hunger/satiety VAS.

What this study cannot tell us

Small sample (n=41). Cannot determine if GLP-1 timing differences cause appetite differences. Secretin unchanged in both groups.

How to read the evidence

Substudy from randomized trial with detailed gut hormone profiling. Small but well-controlled.

When this study was published

Published in 2025.

The bigger picture

The GLP-1 response difference between surgical techniques provides a natural experiment showing how GLP-1 timing affects appetite, informing drug design.

Questions still open

  • Should surgical technique be chosen based on desired GLP-1 response profile?
  • Could pulsatile GLP-1 drug delivery mimic the RYGB early spike?
  • Do GLP-1 timing differences affect long-term weight maintenance?

Common questions

Does the type of weight loss surgery affect GLP-1 levels?
Yes. Roux-en-Y produces a faster, higher GLP-1 spike after eating than one-anastomosis bypass. This may explain why RYGB patients feel less hungry after meals.
If they both cause 25% weight loss, why does the GLP-1 difference matter?
The GLP-1 timing difference affects appetite — RYGB patients felt less hungry sooner after eating. This could influence long-term weight maintenance and eating behavior.

Read the original research

Greater early postprandial GLP-1 increase after Roux-en-Y than one-anastomosis gastric bypass, with unchanged secretin: a randomized controlled trial.

International journal of obesity (2005)

View on PubMed ↗Publisher’s paper ↗

Citation

Heinonen, S; Karppinen, J E; Saarinen, T; Groop, P-H; Juuti, A; Holst, J J; Pietiläinen, K H. (2026). Greater early postprandial GLP-1 increase after Roux-en-Y than one-anastomosis gastric bypass, with unchanged secretin: a randomized controlled trial.. International journal of obesity (2005). https://doi.org/10.1038/s41366-025-02000-3