Roux-en-Y Gastric Bypass and Weight Regain

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)