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 weight loss procedures mentioned on this site. Results may also vary by bariatric surgeon. Ask your doctor for the clinical data stating their results of the procedure they are recommending.

Clinical studies show that, following weight loss 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 weight loss 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.