1. Surgical/anatomical failure such as pouch enlargement, anastomosis dilation, formation of a gastrogastric fistula,

2. Currently on medication that might affect weight gain including GLP-1 analog

3. Inability to provide informed written consent.

4. Any known history of abnormal thyroid function.

5. Females who are pregnant.

Changes in Gut Hormones, Body Composition and Energy Expenditure After Roux-en-Y