Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Observational Study
. 2024 Nov;48(11):1577-1586.
doi: 10.1038/s41366-024-01585-5. Epub 2024 Sep 3.

Metabolic adaptation following gastric bypass surgery: results from a 2-year observational study

Fathimath Naseer  1 , Shu-Dong Zhang  2 , Alexander D Miras  2 , Tamsyn Redpath  1 , Melanie Martin  1 , Adele Boyd  1 , Heather Spence  1 , Dimitri J Pournaras  3 , Zsolt Bodnar  4 , David Kerrigan  5 , Carel W le Roux  6 , M Barbara E Livingstone  1 , Ruth K Price  7
Affiliations
Observational Study

Metabolic adaptation following gastric bypass surgery: results from a 2-year observational study

Fathimath Naseer et al. Int J Obes (Lond). 2024 Nov.

Abstract

Background/objectives: Metabolic adaptation is the lowering of basal metabolic rate (BMR) beyond what is predicted from changes in fat mass (FM) and fat-free mass (FFM) and may hamper weight-loss progression. It is unclear whether metabolic adaptation occurs following gastric bypass surgery (GBP) and if it persists. The aim of this study was to evaluate the reduction in BMR that is not explained by changes in body composition in patients following GBP compared to a weight-stable comparator group.

Subjects: Thirty-one patients [77.4% female; mean BMI 45.5(SD 7.0) kg/m2; age 47.4(11.6)y] who underwent GBP, and 32 time-matched comparators [50% female; BMI 27.2(4.6) kg/m2; age 41.8(13.6)y) were evaluated at 1-month pre-surgery, 3-, 12- and 24-months post-surgery.

Methods: BMR was measured under standardised residential conditions using indirect calorimetry and body composition using DXA. Linear regression analyses assessed metabolic adaptation post-surgery.

Results: After surgery, patients lost a quarter of their body weight [-25.6%(1.8%); p < 0.0001] consisting mainly of FM (4:1 FM to FFM loss ratio) at 24-months post-surgery. Absolute BMR (MJ/d) reduced by 25.7% at 24-months post-surgery with values becoming similar to the comparator group from 3-months post-surgery. Positive associations were observed between changes in BMR and changes in FFM and FM (P < 0.03). Metabolic adaptation was present in patients during the 1) rapid weight loss phase (6.9 kg/month at 3-months post-surgery) (p = 0.011), 2) slower weight loss phase (1.6 kg/month from 3 to 12-months post-surgery) (p < 0.0001), and, 3) weight maintenance phase (24-months post-surgery) (p = 0.00073). However, the degree of metabolic adaptation observed in GBP patients was similar to the weight-stable comparator group (no metabolic adaptation) from 12-months post-surgery onwards (3-months; p = 0.01, 12-months; p = 0.26, 24-months post-surgery; p = 0.70).

Conclusion: These results suggest that there is a potential biological mechanism of surgery that attenuates the expected postoperative downregulation in BMR thus helping GBP patients maintain weight loss.

PubMed Disclaimer

Conflict of interest statement

CLW reports grants from the Irish Research Council, Science Foundation Ireland, Anabio, and the Health Research Board. He serves on advisory boards and speakers panels of Novo Nordisk, Herbalife, GI Dynamics, Eli Lilly, Johnson & Johnson, Glia, Irish Life Health, and Boehringer Ingelheim, Currax, Zealand Pharma, and Rhythm Pharma. ClR is a member of the Irish Society for Nutrition and Metabolism outside the area of work commented on here. He was the chief medical officer and director of the Medical Device Division of Keyron in 2021. Both of these are unremunerated positions. ClR was a previous investor in Keyron, which develops endoscopically implantable medical devices intended to mimic the surgical procedures of sleeve gastrectomy and gastric bypass. No patients have been included in any of Keyron’s studies and they are not listed on the stock market. ClR was gifted stock holdings in September 2021 and divested all stock holdings in Keyron in September, 2021. He continues to provide scientific advice to Keyron for no remuneration. ClR provides obesity clinical care in the Beyond BMI clinic and is a shareholder in the clinic. ADM reports research funding from Novo Nordisk, Fractyl and Randox.

Figures

Fig. 1
Fig. 1. Participant attendance through the four time points of the Gastric Bypass Study.
*Comparators not follow-up during pandemic lockdown. GBP Gastric Bypass Surgery.
Fig. 2
Fig. 2. Mean %proportion of fat mass and fat-free mass per bodyweight for participants at 1-month pre-surgery and at 3-, 12- and 24-months post-surgery.
Data presented as arithmetic mean (SEM) of data available per group at each time point. n: (-1 month pre-surgery: patients 31, comparators 30, 3-months post-surgery: patients 26, comparator 29, 12-months post-surgery: patients 31, comparators 30, 12-months post-surgery: patients 26, comparator 17).
Fig. 3
Fig. 3. Time trajectory plots of residual BMR (resBMR) or magnitude of metabolic adaptation for patient and comparator groups.
Time trajectory plots of resBMR (A) and baseline-weight adjusted resBMR (B) for patient and comparator groups before and 3-, 12- and 24-months after Gastric Bypass Surgery. Errors represents the 95% confidence intervals of the estimated means based on the fitted linear mixed model. resBMR is defined as the difference between the observed BMR (as measured by indirect calorimetry) from the predicted BMR based on the linear regression equations. A Difference between groups: 1-month pre-surgery (p = 1.00), 3-months post-surgery (p = 0.014), 12-months post-surgery (p = 0.26) and 24-months post-surgery (p = 0.70). B Difference between groups:1-month pre-surgery (p = 0.84), 3-months post-surgery (p = 0.76), 12-months post-surgery (p = 1.0) and 24-months post-surgery (p = 1.0).
Fig. 4
Fig. 4. Correlation plots between the extent of metabolic adaptation or residual BMR (resBMR) and changes in body weight in gastric bypass patients.
Correlation plot between the extent of resBMR and changes in body weight in gastric bypass patients at A 3-, B 12- and C 24-months post-surgery. resBMR is defined as the difference between the observed BMR (as measured by indirect calorimetry) from the predicted BMR based on the linear regression equations.
See this image and copyright information in PMC

References

    1. Douglas IJ, Bhaskaran K, Batterham RL, Smeeth L. Bariatric Surgery in the United Kingdom: A Cohort Study of Weight Loss and Clinical Outcomes in Routine Clinical Care. PLoS Med. 2015;12:e1001925. - PMC - PubMed
    1. Versteegden DPA, van himbeeck MJJ, Nienhuijs SW. Improvement in quality of life after bariatric surgery: sleeve versus bypass. Surg Obes Rel Dis. 2018;14:170–4. - PubMed
    1. Ionut V, Bergman RN. Mechanisms Responsible for Excess Weight Loss after Bariatric Surgery. J Diabetes Sci Technol. 2011;5:1263–82. - PMC - PubMed
    1. Ruiz-Lozano T, Vidal J, de Hollanda A, Scheer FAJL, Garaulet M, Izquierdo-Pulido M. Timing of food intake is associated with weight loss evolution in severe obese patients after bariatric surgery. Clinical Nutrition. 2016;35:1308–14. - PubMed
    1. Cadena-Obando D, Ramírez-Rentería C, Ferreira-Hermosillo A, Albarrán-Sanchez A, Sosa-Eroza E, Molina-Ayala M, et al. Are there really any predictive factors for a successful weight loss after bariatric surgery? BMC Endocr Disord. 2020;20:20. - PMC - PubMed

Publication types