Effects of bariatric surgery and dietary intervention on insulin resistance and appetite hormones over a 3 year period

Sci Rep. 2023 Apr 13;13(1):6032. doi: 10.1038/s41598-023-33317-6.


To examine an impact of three types of bariatric surgery compared with dietary intervention (DIET), on concurrent changes in Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) and appetite hormones over 3 years. Fifty-five adults were studied during phase of weight loss (0-12 months) and during weight stability (12-36 months) post intervention. Measurements of HOMA-IR, fasting and postprandial PYY and GLP1, adiponectin, CRP, RBP4, FGF21 hormones and dual-Xray absorptiometry were performed throughout the study. All surgical groups achieved significant reductions in HOMA-IR with greatest difference between Roux-en-Y gastric bypass and DIET (- 3.7; 95% CI - 5.4, - 2.1; p = 0.001) at 12-36 months. Initial (0-12 months) HOMA-IR values were no different to DIET after adjustment for the lost weight. During 12-36 months, after controlling for treatment procedure and weight, for every twofold increase in postprandial PYY and adiponectin, HOMA-IR decreased by 0.91 (95% CI - 1.71, - 0.11; p = 0.030) and by 0.59 (95% CI - 1.10, - 0.10; p = 0.023) respectively. Initial, non-sustained changes in RBP4 and FGF21 were not associated with HOMA-IR values. While initial rapid weight loss reduces insulin resistance, the enhanced secretions of PYY and adiponectin may contribute to weight-independent improvements in HOMA-IR during weight stability.Clinical trial registration: Australian New Zealand Clinical Trials Registry (ANZCTR): ACTRN12613000188730.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adiponectin
  • Adult
  • Appetite
  • Australia
  • Bariatric Surgery*
  • Blood Glucose
  • Gastric Bypass*
  • Humans
  • Insulin
  • Insulin Resistance*
  • Retinol-Binding Proteins, Plasma
  • Weight Loss


  • Adiponectin
  • Insulin
  • Blood Glucose
  • RBP4 protein, human
  • Retinol-Binding Proteins, Plasma

Associated data

  • ANZCTR/ACTRN12613000188730