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. Risks Ten to 20 percent of patients who have weight-loss operations require followup operations to correct complications.
Abdominal hernias are the most common complications requiring followup 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 6 months after surgery.