How Lap Band Surgery Works

Bariatric surgery is a term that applies to a number of surgical procedures that have been developed to treat obesity and surgically induce weight loss. One of these procedures is called gastric banding.

Surgeon Holding Gastric Band

Peter Dazeley / Getty Images

How It Works

Gastric banding—commonly referred to as a “lap-band” when performed laparoscopically—is a form of bariatric surgery. With the gastric band procedure, which is usually performed laparoscopically, an adjustable silicone band is placed around the stomach, dividing the stomach into two pouches: a small upper pouch located above the band, and a larger lower pouch below the band. The small pouch limits the amount of food one can eat at any single sitting, and thus causes a feeling of fullness with less food.

The band can be adjusted by injecting or removing saline from it, thereby decreasing or increasing the size of the opening between the two parts of the stomach. The band is removable and does not permanently alter the anatomy of the stomach or digestive tract.

Gastric banding falls under the category of “restrictive” weight-loss surgical procedures, because it reduces, or restricts, the effective capacity of the stomach to receive food. After the procedure, the patient will be able to consume less food, resulting in a reduction in caloric intake and the desired goal of weight loss.


In a systematic review of studies that have been published to date, one group of researchers found that reported excess weight loss with gastric banding was 45% on average, with a reduction in Type 2 diabetes rates of 28.6%. The reduction in the rate of hypertension (high blood pressure) was 17.4%, and the reduction in hyperlipidemia (high cholesterol) was 22.7%. These numbers were less than those seen with the gastric bypass and gastric sleeve procedures.

Long-term data regarding this procedure looks promising. In a review published in the Annals of Surgery in 2013, several researchers looked at long-term outcomes for patients who underwent gastric banding procedure. After 15 years, participants in the study were still able to keep off nearly half (47%) of the excess weight they carried prior to the procedure.

Side Effects

According to the American Society for Metabolic and Bariatric Surgery, some of the after-effects, such as “dumping syndrome” and diarrhea, associated with other bariatric surgery procedures like gastric bypass are not expected to be associated with laparoscopic adjustable gastric banding. Constipation, however, may be more likely to occur.

Patients who have gastric banding may also experience dysphagia (difficulty swallowing), particularly after having the band tightened or “adjusted.”

With restrictive weight-loss procedures such as gastric banding, malabsorption syndrome does not occur, because food that is eaten eventually does make its way from the upper pouch into the lower pouch, where it is then absorbed normally as it passes through the small intestine and the rest of the digestive system.

However, due to reduced food intake (which is, after all, the point of this procedure), nutritional deficiencies may occur, and at a minimum, it is recommended that gastric banding patients take a complete multivitamin every day. Other nutritional supplements may be recommended based on individual patient needs, and close follow-up with one’s physician is essential.

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  1. O'Brien PE, MacDonald L, Anderson M, Brennan L, Brown WA. Long-term outcomes after bariatric surgery: fifteen-year follow-up of adjustable gastric banding and a systematic review of the bariatric surgical literature. Ann Surg. 2013 Jan;257(1):87-94. doi:10.1097/SLA.0b013e31827b6c02

Additional Reading
  • American Society for Bariatric Surgery Public/Professional Education Committee. Bariatric surgery: postoperative concerns. Published February 2008.
  • Arteburn DE, Fisher DP. The current state of the evidence for bariatric surgery. Editorial. JAMA 2014;312:898-899.
  • Puzziferri N, Roshek TB, Mayo HG, et al. Long-term follow-up after bariatric surgery: a systematic review. JAMA 2014;312:934-942.