Inclusion Criteria:

• BMI 30-50 kg/m^2 for at least 6 months prior to ESG.
• Ages 22-69.
• Diagnosis of UC with plans to undergo or who have already undergone colectomy as part of a plan to pursue eventual 3-stage ileal pouch anal anastomosis (IPAA).
• Willing to adhere to the diet and behavior modifications required for ESG.
• Able to follow the visit schedule.
• Able to provide informed consent.

Exclusion Criteria:

• Prior gastric or bariatric surgery or other alteration to upper gastrointestinal anatomy which would preclude safe or technical performance of ESG.
• Current or recent (last six months) gastric or duodenal ulceration.
• Esophageal or gastric varices.
• Significant motility disorder of the esophagus or stomach.
• Large hiatal hernia measuring > 5 cm or ≤ 5 cm and associated with severe gastroesophageal reflux.
• Severe coagulopathy, hepatic insufficiency, or cirrhosis.
• Gastric mass.
• Presence of any other medical condition which precludes safe performance of elective endoscopy such as poor general health and/or history of severe hepatic, cardiac, or pulmonary disease.
• Serious or uncontrolled psychiatric illness which may compromise patient understanding of procedure or compliance with follow-up visits.
• Unwilling to participate in an established diet and behavior modification program, with routine follow-up.
• Ongoing corticosteroid use at a dose of > 5 mg daily.
• Daily use of anti-inflammatory agents such as non-steroidal medications, or anticoagulants without medical supervision.
• Alcohol or drug addiction.
• Females who are pregnant, nursing, or planning pregnancy within the next year.
• Concomitant use of or unwillingness to avoid any use of weight loss medications, weight loss supplements, or weight loss herbal preparations.
• Has a condition or is in a situation which in the investigator's opinion may put the subject at significant risk or may interfere significantly with the subject's participation in the study.

Eligibility last updated 8/26/22. Questions regarding updates should be directed to the study team contact.