Initially, you will be interviewed over the telephone to provide basic information that will be used to establish your eligibility for gastric bypass surgery. If you meet all the criteria for surgery, you will be asked to come into the Center for Weight Loss to meet with one or more members of the surgical team, who will discuss the details of the procedure, its risks and potential side-effects and the follow-up program.

You will be referred to the Weight Management Program for diet and behavioral modification guidelines before surgery.

As you prepare for gastric bypass surgery, you should eat sensibly - as if you had already had the surgery. Try to limit your total intake of calories by 25%. Do not put yourself on a fad diet or go on an eating binge. Start increasing your physical activity by walking, biking, swimming or other activity you enjoy and would be likely to do after surgery and for the rest of your life.

Having some weight loss before the gastric bypass surgery is helpful. Weight is usually lost from the abdominal organs first. Losing weight can make the difference between having a laparoscopic gastric bypass procedure or more open, traditional gastric bypass surgery.

You should see your primary care physician for a preoperative checkup. Your surgeon may also request other specific consultations or examinations.

Before your gastric bypass surgery date, you will have an appointment with your surgeon, during which time, you should bring up any questions or concerns. You will be given specific instructions about lab work, where and when to arrive, medications and appointments after your surgery.

For the 48 hours before your gastric bypass surgery, you will be on a liquid diet. This includes water, clear juice, tea, coffee, popsicles, gelatin and broth. This is the same diet that you will follow immediately after surgery.

Any heart and blood pressure medications should be taken as usual until the night before your surgery. Other medications require specific recommendations from your doctor. Make sure that you let the nurse coordinator know when you schedule your surgery if you are on any blood thinning agents, such as Coumadin®, Plavix®, aspirin or ibuprofen.

You should continue your clear liquid diet the day before surgery. If you have tendency to be constipated, at noon the day before surgery, take Fleets Phospho-Soda® (1.5 fluid ounces or 3 tablespoons). This a gentle, over-the-counter laxative that cleanses your bowel in preparation for your surgery. You may also flavor the laxative.

After midnight the evening before your gastric bypass surgery, you may not eat or drink anything (not even water) unless told otherwise by your doctor. If you have any questions about your instructions before surgery, contact the nurse coordinator.

Just before your surgery, you will be taken to a room to wait for your procedure. The nurses will start an IV on your arm. Your abdomen will be shaved if necessary, and special pneumatic compression devices will be put on your legs to help prevent blood clots from forming while you are under general anesthesia. You will also be given antibiotics and, possibly, a small dose of heparin (to prevent blood clots). You may be given a sedative if you and your anesthesiologist feel it is necessary.

Gastric bypass surgery is considered major surgery. It can be done either laparoscopically or using an open procedure, in which a vertical incision about eight inches long is made in the abdomen to expose the stomach.

If your surgery is done laparoscopically, your surgeon will make several small incisions, each about an inch long) in various places on your abdomen. Tubes will be put into these small incisions to provide a passageway into your abdomen.

One tube will have a very tiny camera through which your surgeon can see inside your abdomen on a video monitor. Others will allow the surgeon to place the gastric band around your stomach. If any difficulties arise, your surgeon may use an open procedure. In this case, he or she will make a vertical incision about eight inches long in your abdomen to expose your stomach.

Gastric bypass surgery achieves its effects by creating a very small stomach pouch (about thumb-sized) from which the rest of the stomach is permanently divided and separated. The small intestine is cut about 18 inches below the stomach and rearranged to provide an outlet to the small stomach, while maintaining the flow of digestive juices. The lower part of the stomach is bypassed, and food enters the second part of the small bowel about 10 minutes after the beginning of a meal.

This results in your feeling full very early. Even though your portion size may be small, there is no hunger and no feeling of having been deprived. When you feel truly satisfied, you feel indifferent to even the choicest of foods.

Laparoscopic gastric bypass takes between an hour and a half to two hours to complete. If the surgery is done by the open methods, it takes an hour to an hour and a half.

Patients are usually able to leave the hospital two days after surgery, but this depends on your surgeon's recommendation about your specific case. During the first week, your diet should be limited to liquids - the same diet you were given in the hospital, which includes water, juice, tea, coffee, gelatin, popsicles and strained soups. Milk, ice cream and soft food are forbidden at this time.

Gastric bypass surgery reduces the volume of your stomach from about a quart to about one ounce or two tablespoons. Over time the stomach pouch will stretch until it can hold four to eight ounces, or about one half to a whole cup at a time. The size of the opening created between the stomach and small intestine is smaller - about a quarter of an inch wide, which slows the rate at which food is emptied from the stomach into the small intestine.

You should return to your surgeon for routine postoperative care about a week after you leave the hospital. Also at that time you should enroll in the Weight Management Program. Typically it takes 10 to 14 days before you can return to your full daily activities.

Two weeks after your gastric bypass surgery, you can begin to eat soft foods, such as eggs, cream of wheat, mashed potatoes, applesauce, yogurt and cottage cheese, but avoid rice for the moment. In general, you can have food that you do not have to chew to swallow.

Three weeks after gastric bypass surgery you can eat most foods, except for steak and some breads. The more solid the food, the less you can eat and the longer it stays in your stomach pouch.

Over time your body's tolerance for different foods will increase. However, food you tolerate one day may not be tolerated the next. This inconsistency is normal. As you progress, you will find that a normal, balanced meal is difficult because each meal is so small it can encompass only one food group. By varying each meal, a balanced diet can be taken in during the course of the week.

Almost all people who require bariatric surgery have had problems with overeating. The reasons for this are complex and may involve genetics, emotions, upbringing or brain functions. None of this changes after gastric bypass surgery. The only difference is that the upper stomach is now restricted. Eating more than the new pouch can hold or eating too many calorie-dense foods can cause vomiting, expansion of the pouch, weight gain or even rupture of the stomach.

Education, counseling, group support and certain medications can help to prevent overeating. These are just as important as diet to the success of your operation.

You should be monitored closely when you are rapidly losing weight. You will be seen at the Cedars-Sinai Center for Weight Loss about every three months during the first year after surgery.

The amount of weight lost after surgery varies, depending on your age, your weight before surgery, your ability to exercise and the type of weight loss surgery you have. Weight loss averages between 70 and 80% of your excess body weight one year after gastric bypass and is maintained at about 80% for four years after surgery.

Necessary laboratory and diagnostic tests will be recommended when appropriate. You may need to return at unscheduled times. Additionally, you may need to have a periodic assessment. Medications for diabetes or high blood pressure will need to be adjusted by your endocrinologist or primary care physician.

The most common complications occurring in the first few months after gastric bypass surgery are nausea and vomiting. This may happen after eating too fast, drinking liquids while eating, not chewing enough or eating more than the pouch can comfortably hold.

After gastric bypass surgery, you will need to train yourself to chew your food thoroughly, eat slowly and not overeat. While you need to have enough fluids to avoid dehydration and constipation, you should drink liquids between meals rather than at meals because there is less room available now in your stomach. Eventually, the pouch will expand to allow four to five ounces to be eaten at a meal.

Ulcers, extra stomach acid or heartburn may result from having the contents of the stomach flow into the esophagus or from swelling of the pouch. You will need to:

• Avoid citrus juices, which have a high acid content
• Avoid aspirin-type medications such as Motrin®, ibuprofen, Aleve® and Advil®, as they can cause ulcers. Tylenol® can be used for minor pain.
• Take multivitamins to prevent vitamin or mineral deficiencies that can occur if you lose weight too quickly

After gastric bypass surgery, you will not be able to have endoscopic procedures done. Endoscopy is done to diagnose early gastric cancer and other abnormalities of the digestive system. It is a visual examination of the interior structures of the body using an instrument called an endoscope that is passed through your mouth, down your esophagus into your stomach and small intestines.