The actual amount that a weight loss surgery patient will lose after the bariatric procedure is dependent on several factors. These include: 

• Weight loss surgery patient's age
• Weight before bariatric surgery
• Overall condition of weight loss surgery patient's health
• Surgical weight loss procedure performed
• Weight loss surgery patients ability to exercise
• Level of commitment to maintaining dietary guidelines and other follow-up care after the surgical weight loss procedure
• Motivation of weight loss surgery 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 bariatric surgeon. Ask your surgical weight loss specialist for the clinical data stating their results of the weight loss surgery 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. Weight loss surgery 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. Weight loss surgery patients with Type 2 Diabetes tend to show less overall excess weight loss than patients without Type 2 Diabetes. Weight loss surgery has been found to be effective in improving and controlling many obesity-related health conditions. In 2000, a study of 500 weight loss surgery 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 weight loss surgery 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.