Benefits Immediately following surgery, most patients lose weight rapidly and continue to do so until 18 to 24 months after the procedure. Although most patients then start to regain some of their lost weight, few regain it all. Surgery improves most obesity-related conditions. For example, in one study blood sugar levels of most obese patients with diabetes returned to normal after surgery. Nearly all patients whose blood sugar levels did not return to normal were older or had had diabetes for a long time.
Abdominal hernias are the most common complications requiring follow-up surgery.
Less common complications include breakdown of the staple line and stretched stomach outlets. More than one-third of obese patients who have gastric surgery develop gallstones. Gallstones are clumps of cholesterol and other matter that form in the gallbladder. During rapid or substantial weight loss a person's risk of developing gallstones is increased. Gallstones can be prevented with supplemental bile salts taken for the first six months after surgery.