C. Warner Hoornenborg1, 2, Edit Somogyi1, 3, Jan E. Bruggink1, Christina N. Boyle4, Thomas A. Lutz4, Marloes Emous 5, André P. van Beek2, Gertjan van Dijk1
1 Department of Behavioral Neuroscience; Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Groningen, the Netherlands;
2 Department of Endocrinology, University Medical Center Groningen, Groningen, the Netherlands;
3 School of PhD Studies, University of Physical Education, Budapest, Hungary;
4 Institute of veterinary Physiology, Vetsuisse Faculty University of Zurich, Zurich, Switzerland;
5 Department of Bariatric and Metabolic Surgery, Medical Center Leeuwarden, Leeuwarden, the Netherlands.
Abstract
Roux-en-Y gastric bypass (RYGB) surgery results in weight reduction, decreased energy intake and can ameliorate type 2 diabetes. These beneficial effects are usually attributed to a change in hunger and satiety as a consequence of altered concentrations of gut hormones. However the influence of the diet in these effects is unknown. The aim of this study is to investigate the effects of dietary macronutrient content after RYGB surgery effects in male Wistar rats on weight reduction, energy intake and glucose regulation by focusing on eating patterns and beta cell function.
Rats were fed a high fat diet with added sucrose (HF/S) or standard (low fat; LF) diet, which were maintained after RYGB surgery. Body weight, energy intake, high-resolution tracking of meal-related parameters and glucose homeostasis during a mixed meal tolerance test (MMTT; 2 ml sweet/condensed milk) were measured before and after RYGB surgery.
HF/S feeding led to an increased body weight just before Roux-en-Y gastric bypass (RYGB) surgery, but also to enhanced weight loss following RYGB, which finally lead to similar body weights in the HF/S and LF diet groups 3 weeks after RYGB. RYGB surgery reduced energy intake which was mainly due to an increased satiety ratio especially in the HF/S diet group. RYGB surgery did not change the intermeal intervals (p>0.05). In contrast RYGB+ animals ate less (p<0.05) and slower (p<0.05). In addition, diet type independently influenced outcome. HF/S feeding results in shorter meal duration (p<0.01) ,higher ingestion rates (p<0.001 and hyperglycemia with lower circulating levels of insulin (p<0.01) and decreased beta cell sensitivity (calculated by AUCins /AUCgluc, (p<0.01)) after the MMTT.
Conclusion: This study sheds light on the importance of diet after RYGB surgery, as diet type significantly influences meal patterns, postprandial glucose regulation and beta-cell function after RYGB. These results point to an important modifiable mechanism affecting bariatric surgery outcomes.