This study compares eating behaviors, meal size, and the size of the gastric pouch and connection between the gastric pouch and small intestine in patients who had gastric bypass surgery two or more years ago and regained weight compared with patients who had gastric bypass surgery two or more years ago and maintained their weight loss.

Obesity affects a third of adults in the United States. The most effective treatment for weight loss is bariatric surgery, and the most common surgery performed in the US is Roux-en-Y Gastric Bypass (RYGB). However, a significant number of patients regain weight that was lost after surgery. The mechanisms for weight regain are likely multifactorial, but not well understood. Disordered eating behaviors and dilated gastrojejunostomies (GJ), which presumably allows a patient to consume larger portion sizes during a meal, correlate with weight regain. Moreover, some data suggest that changes to the gut anatomy may drive eating behaviors and food preferences. However, no studies have simultaneously evaluated functional gastric volume (the volume of solid or liquid food that can be consumed to a level of comfortable fullness in one sitting), anatomical gastric pouch size and GJ diameter, and eating behaviors in patients who maintained their post RYGB weight compared with patients who have regained weight from their maximum weight loss after RYGB to determine the relationship among post RYGB eating behavior, functional and anatomical gastric pouch size, GJ diameter and weight change. Accordingly, the objectives of this proposal are to compare 1) eating behaviors 2) functional gastric volume and 3) anatomical dimensions of the gastric pouch and GJ in patients who are >2 years post RYGB and have regained >20% of their maximum lost weight and those who are >2 years post RYGB and have maintained at least 90% weight loss since surgery. The following specific aims will be evaluated:

Aim 1. Evaluate whether differences in eating behaviors exist between subjects who have maintained weight loss after RYGB or regained >20% of their maximum lost weight. The investigators hypothesize that subjects who have regained weight after RYGB will have higher scores on binge eating behaviors and an increased craving for sweets compared with patients who have maintained weight loss after RYGB. Eating behaviors will be determined by performing the Yale Food Addiction Scale (YFAS), Eating Disorder Examination (EDE), The Food Craving Inventory (FCI), and the National Cancer Institute (NCI) ASA24.

Aim 2. Evaluate whether differences exist in functional gastric volume between subjects who have maintained weight loss after RYGB or regained >20% of their maximum lost weight. The investigators hypothesize that patients who have regained weight after RYGB will have an increased functional gastric volume to both solids and liquids compared to subjects who have maintained weight loss after RYGB. Functional gastric volume will be measured during both a solid and liquid meal test.

Aim 3. Evaluate whether differences exist in gastric pouch and GJ sizes between subjects who have maintained weight loss after RYGB or regained >20% of their maximum lost weight. The investigators hypothesize that patients who have regained weight after RYGB will have increased gastric pouch size and GJ diameter compared with patients who have maintained their weight loss after RYGB. Anatomical dimensions of the gastric pouch and GJ will be determined by using an articulated measuring tool during upper GI tract endoscopy.

Inclusion Criteria:

• Ages of 21 and 60
• Laparoscopic RYGB surgery >2 years before screening
• Regained >20% weight from their maximum weight lost after surgery or maintained at least 90% weight loss from the maximum weight loss after surgery

Exclusion Criteria:

• Allergy to lidocaine, nut allergies, milk intolerance or any other food allergies/restrictions that are included in our test meals
• A history of alcohol abuse
• Currently consuming >20 gm of alcohol per day
• Greater than 2 points on the MAST
• Severe organ dysfunction
• Anemia (hemoglobin <10mg/dl)
• PT, PTT and INR > 1.5x UNL
• Triglycerides > 400
• LFT > 2x UNL
• Women who are pregnant or lactating
• Participants that smoke greater than 20 pack years
• Actively using illegal drugs
• Depression or other psychological disorders that are untreated
• Diabetics receiving Insulin
• Patients that have been hospitalized and/or had surgery in the last three months that may be unstable (PI will determine this at Physical Exam)

The study population will consist of 20 patients who had laparoscopic RYGB surgery >2 years before screening and have regained >20% weight from their maximum weight lost after surgery and 20 patients who had laparoscopic RYGB surgery >2 years before screening and have maintained at least 90% weight loss from the maximum weight loss after surgery. These patients will be identified from the bariatric surgical population at Washington University School of Medicine.