Obesity Surgery

, Volume 23, Issue 4, pp 531–540

Longitudinal Assessment of Food Intake, Fecal Energy Loss, and Energy Expenditure After Roux-en-Y Gastric Bypass Surgery in High-Fat-Fed Obese Rats

  • Andrew C. Shin
  • Huiyuan Zheng
  • R. Leigh Townsend
  • Laurel M. Patterson
  • Gregory M. Holmes
  • Hans-Rudolf Berthoud
Animal Research

DOI: 10.1007/s11695-012-0846-2

Cite this article as:
Shin, A.C., Zheng, H., Townsend, R.L. et al. OBES SURG (2013) 23: 531. doi:10.1007/s11695-012-0846-2

Abstract

Background

The efficacy of Roux-en-Y gastric bypass (RYGB) surgery to produce weight loss has been well-documented, but few studies have measured the key components of energy balance, food intake, and energy expenditure longitudinally.

Methods

Male Sprague-Dawley rats on a high-fat diet underwent either RYGB, sham operation, or pair feeding and were compared to chow-fed lean controls. Body weight and composition, food intake and preference, energy expenditure, fecal output, and gastric emptying were monitored before and up to 4 months after intervention.

Results

Despite the recovery of initially decreased food intake to levels slightly higher than before surgery and comparable to sham-operated rats after about 1 month, RYGB rats maintained a lower level of body weight and fat mass for 4 months that was not different from chow-fed age-matched controls. Energy expenditure corrected for lean body mass at 1 and 4 months after RYGB was not different from presurgical levels and from all other groups. Fecal energy loss was significantly increased at 6 and 16 weeks after RYGB compared to sham operation, and there was a progressive decrease in fat preference after RYGB.

Conclusions

In this rat model of RYGB, sustained weight loss is achieved by a combination of initial hypophagia and sustained increases in fecal energy loss, without change in energy expenditure per lean mass. A shift away from high-fat towards low-fat/high-carbohydrate food preference occurring in parallel suggests long-term adaptive mechanisms related to fat absorption.

Keywords

High-fat dietBody compositionAdiposityFat preferenceFecal energy lossGastric emptying

Copyright information

© Springer Science+Business Media New York 2012

Authors and Affiliations

  • Andrew C. Shin
    • 1
  • Huiyuan Zheng
    • 1
  • R. Leigh Townsend
    • 1
  • Laurel M. Patterson
    • 1
  • Gregory M. Holmes
    • 1
  • Hans-Rudolf Berthoud
    • 1
  1. 1.Neurobiology of Nutrition Laboratory, Pennington Biomedical Research CenterLouisiana State UniversityBaton RougeUSA