During gastric bypass surgery, the surgeon divides the stomach into two portions. The small upper portion forms a gastric bypass pouch, which is where the patient's food goes after the procedure. This pouch is extremely small and only holds about 1 ounce (about 28 grams) of food. The smaller stomach causes the patient to feel full on less food, which helps with portion control and weight loss. Over time, the pouch stretches to accommodate more food.
It is important that weight loss surgery patients follow their doctors' advice and instructions after the procedure so that they do not stretch the pouch too soon or continue overeating once the pouch has stretched to its mature size. The gastric bypass pouch is at its smallest during the first six months after surgery. Patients should sip water throughout the day to prevent dehydration, though they should not drink with meals. Meals should be about five hours apart to prevent patients from getting so hungry that they force themselves to overeat and stretch the pouch too quickly. Solid foods, such as finely cut meat, vegetables, and fruits, stay in the pouch longer and help retain the feeling of fullness.
Gastric bypass patients should strive to eat their small meals within five to 15 minutes to create a satisfying sense of fullness. Soft foods and liquid foods, such as soup, empty out of the gastric bypass pouch faster, which may encourage the patient to eat more, hindering weight loss. Most doctors advise weight loss surgery patients to sip water and other calorie-free beverages if they get hungry between meals to prevent overfilling the pouch.
During the first several weeks following surgery, many patients may vomit as they learn to accommodate their meals and eating habits to the size of the gastric bypass pouch. Many patients are restricted to a liquid diet for the first four to six weeks following surgery, and solid foods are gradually reintroduced. Grains, rice, and pasta can swell in the pouch after the patient consumes them and cause vomiting. Gastric bypass patients who struggle with vomiting after the procedure can measure their food in 1 ounce (28 gram) portions and wait several minutes between consuming these small-sized portions to learn how to manage their gastric bypass pouches.
Patients should follow up with their doctors at regular intervals after undergoing gastric bypass surgery. Asking questions about the pouch and mentioning any difficulties helps avoid problems and enables the doctor to address any issues the patient is having during the recovery process. While almost all patients lose weight in the first six months following the surgery, it is quite possible to stop losing weight or regain some or all of the lost weight if the patient does not manage his gastric bypass pouch appropriately.