Calorie restriction and not glucagon-like peptide-1 explains the acute improvement in glucose control after gastric bypass in Type 2 diabetes

Diabet Med. 2016 Dec;33(12):1723-1731. doi: 10.1111/dme.13257. Epub 2016 Oct 8.


Aims: To compare directly the impact of glucagon-like peptide-1 secretion on glucose metabolism in individuals with Type 2 diabetes listed for Roux-en-Y gastric bypass surgery, randomized to be studied before and 7 days after undergoing Roux-en-Y gastric bypass or after following a very-low-calorie diet.

Methods: A semi-solid meal test was used to investigate glucose, insulin and glucagon-like peptide-1 response. Insulin secretion in response to intravenous glucose and arginine stimulus was measured. Hepatic and pancreatic fat content was quantified using magnetic resonance imaging.

Results: The decrease in fat mass was almost identical in the Roux-en-Y gastric bypass and the very-low-calorie diet groups (3.0±0.3 and 3.0±0.7kg). The early rise in plasma glucose level and in acute insulin secretion were greater after Roux-en-Y gastric bypass than after a very-low-calorie diet; however, the early rise in glucagon-like peptide-1 was disproportionately greater (sevenfold) after Roux-en-Y gastric bypass than after a very-low-calorie diet. This did not translate into a greater improvement in fasting glucose level or area under the curve for glucose. The reduction in liver fat was greater after Roux-en-Y gastric bypass (29.8±3.7 vs 18.6±4.0%) and the relationships between weight loss and reduction in liver fat differed between the Roux-en-Y gastric bypass group and the very-low-calorie diet group.

Conclusions: This study shows that gastroenterostomy increases the rate of nutrient absorption, bringing about a commensurately rapid rise in insulin level; however, there was no association with the large post-meal rise in glucagon-like peptide-1, and post-meal glucose homeostasis was similar in the Roux-en-Y gastric bypass and very-low-calorie diet groups. (Clinical trials registry number: ISRCTN11969319.).

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adipose Tissue / metabolism
  • Adult
  • Aged
  • Amino Acids
  • Arginine / administration & dosage
  • Arginine / pharmacology
  • Blood Glucose / biosynthesis
  • Blood Glucose / metabolism
  • Body Composition
  • Caloric Restriction*
  • Chromium
  • Diabetes Mellitus, Type 2 / metabolism
  • Diabetes Mellitus, Type 2 / therapy*
  • Female
  • Gastric Bypass*
  • Glucagon-Like Peptide 1 / metabolism*
  • Glucose / administration & dosage
  • Glucose / pharmacology
  • Glycated Hemoglobin A / metabolism
  • Humans
  • Insulin / metabolism
  • Insulin Resistance / physiology
  • Insulin Secretion
  • Lipase / genetics
  • Liver / chemistry
  • Male
  • Membrane Proteins / genetics
  • Middle Aged
  • Nicotinic Acids
  • Pancreas / chemistry
  • Triglycerides / metabolism


  • Amino Acids
  • Blood Glucose
  • Glycated Hemoglobin A
  • Insulin
  • Membrane Proteins
  • Nicotinic Acids
  • Triglycerides
  • glucose tolerance factor
  • Chromium
  • Glucagon-Like Peptide 1
  • Arginine
  • Lipase
  • adiponutrin, human
  • Glucose

Associated data

  • ISRCTN/ISRCTN11969319