Weight loss surgery is major surgery. Although most patients enjoy an improvement in obesity-related health conditions (such as mobility, self-image and self-esteem) after the successful results of weight loss surgery, these results should not be the overriding motivation for having the procedure. The goal is to live better, healthier and longer.

That is why you should make the decision to have weight loss surgery only after careful consideration and consultation with an experienced bariatric surgeon or a knowledgeable family physician. A qualified surgeon should answer your questions clearly and explain the exact details of the procedure, the extent of the recovery period and the reality of the follow-up care that will be required. They may, as part of routine evaluation for weight loss surgery, require that you consult with a dietician/nutritionist and a psychiatrist/therapist. This is to help establish a clear understanding of the post-operative changes in behavior that are essential for long-term success.

It is important to remember that there are no ironclad guarantees in any kind of medicine or surgery. There can be unexpected outcomes in even the simplest procedures. What can be said, however, is that weight loss surgery will only succeed when the patient makes a lifelong commitment. Some of the challenges facing a person after weight loss surgery can be unexpected. Lifestyle changes can strain relationships within families and between married couples. To help patients achieve their goals and deal with the changes surgery and weight loss can bring, most bariatric surgeons offer follow-up care that includes support groups, dieticians and other forms of continuing education.

Ultimately, the decision to have the procedure is entirely up to you. After having heard all the information, you must decide if the benefits outweigh the side effects and potential complications. This surgery is only a tool. Your ultimate success depends on strict adherence to the recommended dietary, exercise and lifestyle changes.

How Effective Is Surgery? 
The actual weight a patient will lose after the procedure is dependent on several factors. These include:

• Patient's age
• Weight before surgery
• Overall condition of patient's health
• Surgical procedure
• Ability to exercise
• Commitment to maintaining dietary guidelines and other follow-up care
• Motivation of patient and cooperation of their family, friends and associates

In general, weight loss surgery success is defined as achieving loss of 50% or more of excess body weight and maintaining that level for at least five years. Clinical data will vary for each of the different procedures mentioned on this site. Results may also vary by surgeon. Ask your doctor for the clinical data stating their results of the procedure they are recommending.

Clinical studies show that, following surgery, most patients lose weight rapidly and continue to do so until 18 to 24 months after the procedure. Patients may lose 30 to 50% of their excess weight in the first six months and 77% of excess weight as early as 12 months after surgery. Another study showed that patients can maintain a 50-60% loss of excess weight 10-14 years after surgery. Patients with higher initial BMIs tend to lose more total weight. Patients with lower initial BMIs will lose a greater percentage of their excess weight and will more likely come closer to their ideal body weight. Patients with Type 2 Diabetes tend to show less overall excess weight loss than patients without Type 2 Diabetes. The surgery has been found to be effective in improving and controlling many obesity-related health conditions. A 2000 study of 500 patients showed that 96% of certain associated health conditions studied (back pain, sleep apnea, high blood pressure, diabetes and depression) were improved or resolved. For example, many patients with Type 2 Diabetes, while showing less overall excess weight loss, have demonstrated excellent resolution of their diabetic condition, to the point of having little or no need for continuing medication.

The Gastrointestinal Tract
To better understand how weight loss surgery works, it is important to understand how your gastrointestinal tract functions. As the food you consume moves through the tract, various digestive juices and enzymes are introduced at specific stages that allow absorption of nutrients. Food material that is not absorbed is then prepared for elimination. A simplified description of the gastrointestinal tract appears below. Your doctor can provide a more detailed description to help you better understand how weight loss surgery works.

1. The esophagus is a long muscular tube, which moves food from the mouth to the stomach.
2. The abdomen contains all of the digestive organs.
3. The stomach, situated at the top of the abdomen, normally holds just over 3 pints (about 1500 ml) of food from a single meal. Here the food is mixed with an acid that is produced to assist in digestion. In the stomach, acid and other digestive juices are added to the ingested food to facilitate breakdown of complex proteins, fats and carbohydrates into small, more absorbable units.
4. A valve at the entrance to the stomach from the esophagus allows the food to enter while keeping the acid-laden food from "refluxing" back into the esophagus, causing damage and pain.
5. The pylorus is a small round muscle located at the outlet of the stomach and the entrance to the duodenum (the first section of the small intestine). It closes the stomach outlet while food is being digested into a smaller, more easily absorbed form. When food is properly digested, the pylorus opens and allows the contents of the stomach into the duodenum.
6. The small intestine is about 15 to 20 feet long (4.5 to 6 meters) and is where the majority of the absorption of the nutrients from food takes place. The small intestine is made up of three sections: the duodenum, the jejunum and the ileum.
7. The duodenum is the first section of the small intestine and is where the food is mixed with bile produced by the liver and with other juices from the pancreas. This is where much of the iron and calcium is absorbed.
8. The jejunum is the middle part of the small intestine extending from the duodenum to the ileum; it is responsible for digestion.
9. The last segment of the intestine, the ileum, is where the absorption of fat-soluble vitamins A, D, E and K and other nutrients are absorbed.
10. Another valve separates the small and large intestines to keep bacteria-laden colon contents from coming back into the small intestine.
11. In the large intestines, excess fluids are absorbed and a firm stool is formed. The colon may absorb protein, when necessary.