The Effect of Bariatric Surgery on Metabolism, the Metabolome and Microbiome in Patients With Type 2 Diabetes

Roux-en-y gastric bypass (RYGB) surgery leads to improvements in diabetes that occurs even
before any significant weight loss is seen. What are the reasons for this? There is evidence
in animals that changes in the composition of gut bacteria after RYGB may be responsible for
improvements in how glucose is metabolized in the body. The study aims to correlate changes
in the bacterial composition of the gut that occurs after surgery with improvements in
glucose metabolism in people with type 2 diabetes. The investigators will do this by using
validated methods to measure glucose metabolism and cutting edge technology to analyze the
gut microbiome. A parallel group of patients with similar weight, height and age will undergo
caloric restriction alone to mimic weight loss seen after RYGB. Participants will also
undergo similar glucose metabolism studies and analysis of their gut bacterial composition.
Thus, any difference seen between groups can be attributed to the surgery itself and may lead
to identification of novel therapeutic options for diabetes.

Inclusion Criteria:

- Age 20-65 years of age.

- Seen at Mayo Clinic Nutrition Clinic and have received authorization for RYGB surgery.

- Type 2 Diabetes Mellitus or impaired fasting glucose with BMI >35 AND not interested
in surgery but are interested in supervised caloric restriction.

Exclusion Criteria:

- Previous treatment with thiazolidinediones.

- Chronic antibiotic therapy.

- Active microvascular or macrovascular complications of diabetes.