Weight Loss, Appetite Suppression, and Changes in Fasting and Postprandial Ghrelin and peptide-YY Levels After Roux-en-Y Gastric Bypass and Sleeve Gastrectomy: A Prospective, Double Blind Study

Ann Surg. 2008 Mar;247(3):401-7. doi: 10.1097/SLA.0b013e318156f012.


Background: Bariatric surgery is currently the most effective treatment in morbidly obese patients, leading to durable weight loss.

Objective: In this prospective double blind study, we aim to evaluate and compare the effects of laparoscopic Roux-en-Y gastric bypass (LRYGBP) with laparoscopic sleeve gastrectomy (LSG) on body weight, appetite, fasting, and postprandial ghrelin and peptide-YY (PYY) levels.

Methods: After randomization, 16 patients were assigned to LRYGBP and 16 patients to LSG. Patients were reevaluated on the 1st, 3rd, 6th, and 12th postoperative month. Blood samples were collected after an overnight fast and in 6 patients in each group after a standard 420 kcal mixed meal.

Results: Body weight and body mass index (BMI) decreased markedly (P < 0.0001) and comparably after either procedure. Excess weight loss was greater after LSG at 6 months (55.5% +/- 7.6% vs. 50.2% +/- 6.5%, P = 0.04) and 12 months (69.7% +/- 14.6% vs. 60.5% +/- 10.7%, [P = 0.05]). After LRYGBP fasting ghrelin levels did not change significantly compared with baseline (P = 0.19) and did not decrease significantly after the test meal. On the other hand, LSG was followed by a marked reduction in fasting ghrelin levels (P < 0.0001) and a significant suppression after the meal. Fasting PYY levels increased after either surgical procedure (P < or = 0.001). Appetite decreased in both groups but to a greater extend after LSG.

Conclusion: PYY levels increased similarly after either procedure. The markedly reduced ghrelin levels in addition to increased PYY levels after LSG, are associated with greater appetite suppression and excess weight loss compared with LRYGBP.

Publication types

  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Appetite / physiology*
  • Bariatric Surgery*
  • Double-Blind Method
  • Gastrectomy / methods*
  • Gastric Bypass*
  • Ghrelin / blood*
  • Humans
  • Peptide YY / blood*
  • Prospective Studies
  • Weight Loss / physiology*


  • Ghrelin
  • Peptide YY