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Updated: Jun 5, 2026
07:37
Roux-en-Y Gastric Bypass Operation in Rats
Published on: June 11, 2012
Abnormal glucose tolerance testing following gastric bypass demonstrates reactive hypoglycemia
Mitchell Roslin1, Tanuja Damani, Jonathan Oren
1Department of Surgery, Lenox Hill Hospital, and Department of Orthopedic Surgery, New York University, 186 East 76th Street, New York, NY 10021, USA.
Surgical Endoscopy
|December 25, 2010
Summary
Reactive hypoglycemia is common after Roux-en-Y gastric bypass (RYGB) surgery, potentially causing weight regain. Glucose tolerance tests (GTT) are crucial for post-RYGB screening to identify this condition.
Area of Science:
- Bariatric Surgery
- Endocrinology
- Gastroenterology
Background:
- Reactive hypoglycemia and weight regain are reported after Roux-en-Y gastric bypass (RYGB).
- A 4-hour glucose tolerance test (GTT) was employed to evaluate hypoglycemia incidence and severity.
Purpose of the Study:
- To assess the incidence and characteristics of reactive hypoglycemia post-RYGB.
- To investigate the relationship between abnormal glucose tolerance, weight regain, and preoperative diabetes status.
Main Methods:
- A 4-hour GTT with insulin level measurements was performed on 36 patients at least 6 months post-RYGB.
- Patient data included age, preoperative BMI, percent excess BMI lost, weight change, and follow-up duration.
Main Results:
- 89% of patients exhibited abnormal GTT results.
- 72% of patients showed evidence of reactive hypoglycemia, with 91% of those experiencing weight regain also showing hypoglycemia.
- Preoperative diabetes persisted in 50% of diabetic patients; reactive hypoglycemia was common in non-diabetic patients.
Conclusions:
- Abnormal GTT is a frequent finding after RYGB.
- Reactive hypoglycemia, potentially linked to altered food transit and lack of a pyloric valve, may contribute to weight regain.
- GTT should be a routine part of post-RYGB follow-up; further research on pylorus preservation is warranted.
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