How Lap Band Surgery Works

Surgeon Holding Gastric Band
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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 gastric banding.

How It Works

Gastric banding—commonly referred to as a “lap-band” when done laparoscopically—is a form of bariatric surgery. With the gastric band procedure, which is usually performed laparoscopically, a 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 that 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.


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% with a gastric band, 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.

In spite of the evidence thus far, however, longer-term follow-up studies are needed, as no studies of bariatric surgery appear to report outcomes beyond five years. Thus, although the initial weight loss numbers are known, what is not known is how much weight loss is maintained over seven or ten years or even longer.

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, due to the fact that 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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Article Sources

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  • 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.