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Risks & Benefits of Weight Loss Surgery

Bariatric surgery, also known as weight loss surgery, comes with risks and benefits. We encourage you to discuss these with your family and doctors before you choose to have a weight loss procedure at NYU Langone’s Weight Management Program

Benefits of Weight Loss Surgery

Weight loss surgery can improve your quality of life in many ways. The constant feelings of hunger you experience prior to surgery diminish and you may become less preoccupied with food. As you lose significant amounts of weight, you find that you have more energy, and everyday activities no longer leave you short of breath.

Just a few months after surgery, you may begin to feel proud of the way you look and feel as you start to fit into smaller clothing. As your focus on food lessens, you may discover more outside interests. Feelings of self-consciousness may be gradually replaced by feelings of confidence and self-control.

Man Holding Fruit at Fruit Stand

Bariatric surgery not only helps you lose excess weight and keep it off, it also improves or eliminates most medical problems associated with obesity. When you begin to lose weight, you can usually cut down, or stop taking, medications for these various conditions. Remarkably, many people with diabetes see their blood sugar levels normalize within days of the operation.

It is important to remember, though, that bariatric surgery is not a magic elixir for weight loss. It is a tool to be used along with diet and exercise to achieve a healthier life. Surgery is not a substitute for a healthy lifestyle; rather, it allows diet and exercise to actually work.

The ultimate measures of bariatric surgery are how much weight is lost, how long the weight loss lasts, the improvement in your health and quality of life, and safety. 

Risks of Weight Loss Surgery

Bariatric surgery does come with several risks to your health. 


Atelectasis is the partial collapse of the lungs. It is very common after surgery, especially in people who are obese, when the bottom portion of the lungs are squashed, opening only with coughing and very deep breaths. 

This can lead to problems such as fever, pneumonia, or shortness of breath. Atelectasis can be prevented or alleviated by performing deep-breathing exercises and coughing after surgery.

Pulmonary Embolism

A pulmonary embolism is a blood clot in the lungs. The problem begins in the legs, where blood clots can form in the veins of the calves or thighs, especially if the legs are stationary. Such clots can cause swelling or pain in the leg. However, they present the most danger if they break off and travel to the lungs. 

A large clot can cause shortness of breath or completely block blood from entering the lungs, causing death. People who are overweight have a higher risk of forming blood clots in the legs, particularly during or soon after surgery.

To prevent pulmonary emboli during and after surgery, your legs are fitted with sequential compression boots that act like blood pressure cuffs that massage your legs and prevent blood clots from forming. You are also given a small dose of blood thinner, called heparin, at the time of surgery. The best prevention, though, is to get out of bed and walk around soon after surgery.

Bowel Leakage

Leakage of bowel contents—from the new connection between the stomach and the small intestine or between two parts of intestine—is the most serious complication of gastric bypass and biliopancreatic diversion. 

A leak from a burst staple line in the sleeve gastrectomy can also occur. Such leaks can cause a high heart rate, pain in the abdomen or back, fever, infection, and even death. Treatment usually entails antibiotic therapy or surgical repair, depending on the size of the leak.

In the Roux-en-Y gastric bypass, a new stomach pouch is made from the top of the stomach and the rest of the organ is detached and left alone. The stomach remnant remains alive, but it shrinks in size. In rare instances, a blockage can develop in the stomach remnant, causing a backup of fluid and leakage of bowel contents. 

This condition can be difficult to diagnose because it does not cause vomiting. If it occurs, you need to have an abdominal CT scan. If your stomach is found to be inflated, it is deflated with a small needle, after you are given a local anesthesia. 

Difficulty Eating

In gastric bypass surgery, the connection between the new stomach pouch and the intestine is created using a stapling technique. As with all surgical healing, a scar forms. Sometimes, this scar can tighten around the connection and cause it to narrow to a point where food cannot pass through. 

This problem typically occurs four to six weeks after surgery. It can be corrected by stretching the narrowed opening, which is done endoscopically. A gastroenterologist inserts a tube down your throat while you are lightly sedated to widen the opening.

In people who have had a sleeve gastrectomy, the banana-shaped stomach may become too narrow due to scar tissue, leading to difficulty eating or even drinking. Stretching by endoscopy may be necessary; or in extreme cases, corrective surgery may be required.

In people who have had gastric band surgery, the opening between the upper and lower stomach pouches can also become too narrow. This can be corrected with a simple adjustment to loosen the band.

In rare instances, the gastric band can slip and cause constant regurgitation and heartburn. Symptoms can be relieved by loosening the band in an office visit. 

The diagnosis is confirmed with a barium-swallow study. If this happens, the band would likely need to be repositioned with another operation, which is done laparoscopically. A special diet of liquids, shakes, and purees for the first month after surgery helps prevent this condition.

Other Risks

On rare occasions after gastric band surgery, the band erodes into the stomach. This does not cause pain, but may result in inadequate weight loss. This is diagnosed by endoscopy. The condition is repaired with surgery, which we perform laparoscopically.

As with any operation, the incision site can become infected. In overweight patients with more fat in the abdominal walls, the infection can be deeper than usual. You are prescribed oral antibiotics for a minor infection. Deeper, more serious infections may require opening the wound and packing it with gauze in addition to giving antibiotics.