Overview
Bariatric surgery markedly improves glycemic control in persons with Type 2 Diabetes (T2D). Roux-en-Y gastric bypass (RYGB), a procedure that bypasses the upper gastrointestinal (UGI) tract, results in greater rates of diabetes resolution compared to methods that leave the UGI tract intact. Studies suggest that mechanisms beyond weight-loss account for the superiority of RYGB compared to other surgical methods. These weight-loss independent metabolic effects may involve increased postprandial production and release of nutrition- responsive hormones. Fibroblast growth factor 21 (FGF21) is a nutrition-adaptive hormone with the potential to alleviate symptoms of diabetes and obesity. Preliminary data therefore suggest that RYGB surgery may alter postprandial FGF21 regulation which could be important for achieving post-meal nutrient homeostasis. Therefore, the goal of this study is to test how nutrient content of the meal affects FGF21 concentrations before and after weight loss induced by RYGB or very low calorie diet (VLCD) therapy. The importance of FGF21 for glucose, insulin, triglyceride, and adipose tissue and muscle metabolism in these two groups will also be tested.
Eligibility
Inclusion Criteria:
Surgery Group (RYGB):
- Males and Females
- Scheduled for RYGB surgery
- Body Mass Index 35-55 kg/m²
- Without Type 2 Diabetes (T2D)
VLCD group:
- Males and Females
- Body Mass Index 35-55 kg/m²
- Without Type 2 Diabetes (T2D)
Exclusion Criteria:
Surgery Group (RYGB):
- Regular use of tobacco products
- Previous intestinal resection
- Pregnant or breastfeeding
- Evidence of significant organ system dysfunction or disease other than obesity and T2D
- Use of any medication that might, in the opinion of the investigator, affect metabolic function
- Exercise ≥90 minutes per week
- Use or past use of hormone replacement therapy within the past 6 months
VLCD Group:
- Regular use of tobacco products
- Previous intestinal resection
- Pregnant or breastfeeding
- Evidence of significant organ system dysfunction or disease other than obesity and T2D
- Use of any medication that might, in the opinion of the investigator, affect metabolic function
- Exercise ≥90 minutes per week
- Use or past use of hormone replacement therapy within the past 6 months