Surgical Weight Loss Therapies

What Are Surgical Weight Loss Therapies?

What Are Surgical Weight Loss Therapies?

Surgical weight loss therapies, also known as bariatric surgeries, offer individuals who are 80 or more pounds overweight an opportunity for sustained weight loss and improved long-term health.

NewYork-Presbyterian’s surgeons are leaders in bariatric surgery procedures and pioneered the concept of metabolic surgery: weight loss surgery to improve diabetes and manage blood sugar, high blood pressure, and high cholesterol/triglycerides

Our clinical and preclinical research has clarified how bariatric surgical techniques influence the regulation of hormones to improve overall health, not just achieve a reduction in body weight.

Types of Weight Loss Surgery


There are various options when it comes to weight loss surgeries. These options include gastric sleeve, gastric bypass, and adjustable gastric band. Based on your weight loss journey, your bariatric surgeon will determine the right procedure type.

Sleeve gastrectomy

Sleeve gastrectomy, now the most common weight loss operation in the United States, is a surgical procedure in which the stomach size is reduced to the shape of a banana or “sleeve,” restricting the amount of food you can eat.

How it is performed. The surgeon removes 60 to 75 percent of your stomach. Although originally devised as the first stage of a two-stage procedure for super-obese or high-risk patients, we now commonly use sleeve gastrectomy to achieve weight loss in people with a body mass index (BMI) over 35 and significant comorbid conditions.

Sleeve gastrectomy effectiveness. People undergoing this procedure usually lose 20 to 25 percent of their total body weight over a six-to-12-month period. When performed alone, sleeve gastrectomy also decreases the production of the hormone ghrelin, reducing feelings of hunger and resulting in weight loss comparable to gastric bypass.

Roux-en-Y gastric bypass surgery

Roux-en-Y gastric bypass, or gastric bypass, is the second-most common weight loss surgery in the United States.

How it is performed. Your surgeon creates a small pouch in the top of your stomach, forming a “new stomach,” which will limit the amount of food you can eat during a meal, helping you feel fuller sooner.

The surgeon then creates a small opening in the pouch and attaches that opening to a section of your small intestine. The reconnected intestine causes food to bypass part of the intestine, so some of the nutrients and fewer calories will not be absorbed.

The altered anatomy also changes your hormones, which also helps you feel full sooner.

Gastric bypass surgery effectiveness. Most people lose 30 to 35 percent of their total body weight within 12 to 18 months after surgery, with most of that loss sustained over the next ten years. Many obese people with diabetes find that with this surgery, their diabetes resolves rapidly — sometimes within days or weeks.

NewYork-Presbyterian surgeons have more than two decades of experience performing this procedure.

Biliopancreatic diversion with duodenal switch (BPD-DS)

Biliopancreatic diversion with duodenal switch (BPD-DS), also referred to as duodenal switch, is a complex procedure that promotes weight loss by combining two procedures: sleeve gastrectomy, to reduce food intake, and intestinal bypass, to limit absorption in the intestine.

It combines the hormonal changes of both operations and is very effective against diabetes.

How it is performed. With this procedure, the surgeon removes about 60 to 70 percent of your stomach so that it takes the shape of a banana (sleeve gastrectomy). The lower intestine is then divided much further downstream than with gastric bypass so that two-thirds or more of the intestine is bypassed, leaving only a few feet of the intestine where food and digestive enzymes meet; this is the intestinal bypass portion of the operation.

The name “duodenal switch” comes from the fact that in this operation, the intestinal bypass starts at the duodenum (the first part of the intestine), which is divided and attached to the lower portion of the small intestine (the ileum).

Duodenal switch effectiveness. Most people lose 35 to 40 percent of their total body weight over a two-year period, with 70 percent of the weight loss sustained beyond 10 years.

Single anastomosis duodenal switch (SADI/SIPS)

Similar to BPD-DS, the single anastomosis duodenal switch — also known as single anastomosis duodeno-ileal bypass (SADI), stomach intestinal pylorus-sparing surgery (SIPS), or loop duodenal switch — has the dual effect of restricting stomach size as well as inhibiting the absorption of some nutrients to help you achieve and maintain your weight loss goals.

In this procedure, however, the intestine is rerouted at a single point. The effective bypass in this procedure is slightly less than that of a traditional duodenal switch, yet still induces significant weight loss. SADI/SIPS is a simpler procedure than BPD-DS and is more effective than sleeve gastrectomy alone.

Laparoscopic gastric banding

Adjustable gastric banding (Lap-Band or Realize Band) is less invasive than other procedures because neither your stomach nor intestine is cut. Instead, a band is placed around your stomach that can be adjusted to restrict the amount of food you eat before feeling full.

How it is performed. Your surgeon places an adjustable band around the upper part of your stomach to create a small stomach pouch above the band. By adding fluid to the band after you recover from surgery, the surgeon adjusts the opening size between the smaller, upper pouch and the remaining lower portion of your stomach.

The tightness of the band opening controls the passage of food between the two parts of your stomach, giving you a feeling of fullness after eating that lasts significantly longer than it would without the band. Your surgeon works closely with you to tailor the band adjustment to your needs.

Gastric banding effectiveness. Losing weight after adjustable gastric band surgery is more gradual than with gastric bypass. You can expect to lose 15 to 20 percent of your total body weight within two years of surgery. The amount of weight lost depends on how you adapt and maintain new eating habits, regular exercise, and follow-up with your care team.

Short-term and especially long-term results are not as good as those achieved with other surgical weight loss operations but better than those associated with endoscopic treatments.



Despite being one of the safest medical procedures available, bariatric surgery, like any other surgical procedure, involves some risks.  

The risk will vary according to the type of weight loss procedure. Your bariatric surgeon will thoroughly explain all the risks and complications to you. 

Risks of bariatric surgery include:

  • Pulmonary embolism involves the sudden formation of a blood clot that stops blood flow to an artery in the lung. Usually, the blood clot starts in a deep vein in the leg and travels to the lung.
  • Difficulty eating: Individuals who have undergone weight loss surgery won’t be able to eat as much as they did before the surgery. Patients may experience difficulty digesting certain foods the way they should. Unpleasant symptoms, such as nausea and vomiting, may occur.
  • Intestinal leakage: A leak can occur when the cut-line of the stomach (the connection between the stomach and intestine) does not heal properly, potentially leading to infections and the need for reoperation. This is a rare event, affecting about 1 percent of patients.
  • Nutritional deficiencies: Depending on the type of bariatric procedure, some patients may develop nutritional deficiencies. However, these are generally avoidable with proper bariatric follow-up.
  • Gallstones: Gallstones can develop when a patient experiences rapid weight loss, but this is generally avoidable by taking a prophylactic (preventative) medication that your doctor will prescribe for the first six months after surgery.

Preparing for a Weight Loss Surgery


Weight loss surgery is a breakthrough in modern medical technology. Regardless, patients must prepare before surgery to have the highest chance of success.

As part of the screening processes, patients will typically meet with a team of several health care professionals, such as an internist, a dietitian, a psychiatrist or psychologist, and a bariatric surgeon. This team’s job is to determine whether you’re a good candidate for weight loss surgery. 

  • Internist: An internist or primary care physician will help patients obtain medical clearance in preparation for bariatric surgery. The doctor will also guide you through post-surgical care.
  • Dietitian: A registered dietitian (RD) helps patients prepare for surgery by assisting in diet and lifestyle changes. The information taught before surgery will help patients develop and adhere to sustainable weight loss practices post-surgery.  
  • Psychiatrist or psychologist : A patient must complete and pass a psychological evaluation before having bariatric surgery. A psychiatric assessment aims to understand the patient’s motivation and evaluate readiness and behavioral and emotional factors that may affect the patient’s ability to copy and adjust after the procedure.
  • Bariatric surgeon: Your bariatric surgeon oversees medical weight management and pre- and postoperative screening.

What to Expect After Weight Loss Surgery

After the Surgery

Postoperative recovery for bariatric patients will not look the same for every patient. Depending on your stage of recovery, your health professional may recommend multiple diets.

In general, most people getting weight loss surgery expect to lose a lot of weight and expect improvement in weight-related medical conditions like type 2 diabetes or sleep apnea.

Most people should expect to remain in the hospital for one-night post-surgery and return to normal activities within three to five weeks.

Possible post-surgical complications include blood clots, blood in stool, wound infections, gallstones, and constipation.

Because the stomach is much smaller after surgery, patients must adopt lifestyle changes such as eating small, frequent meals.

Because weight loss surgery changes how your body absorbs nutrients, you may need nutritional supplements in your diet with vitamins and minerals. A registered dietitian can advise on developing and sticking with a healthy, sustainable post-surgical diet plan. 

What If I need weight loss surgery again?

Revisional surgery is an option for some people who have already undergone a weight loss procedure and need another to repair the first one, or for those who have gained or have not lost enough weight after the first operation.

NewYork-Presbyterian surgeons are among the most experienced in the region — having performed revisional procedures for nearly two decades — and have created procedures that lower the risk of a second surgery.

Patients often need revision surgery to convert an older weight loss procedure to a more modern, effective one, such as the Roux-En-Y gastric bypass or a duodenal switch.



Most people who get weight loss surgery can expect to lose about 25 to 30 percent of their total body weight. This exact amount, of course, depends on the individual and the type of procedure performed. Most of this weight may be lost within the first 12 to 18 months following surgery.

There are risks with all surgical procedures, but gastric bypass surgery is one of the safest procedures around. The Roux-En-Y gastric bypass, for instance, uses a laparoscopic approach, which reduces complications.

There is an evaluation process to determine eligibility, but after the initial consultation, most people should expect at least a two-month wait time.

Bariatric surgery is one of the safest weight loss surgical procedures available today. Laparoscopic surgery techniques are used in any weight loss procedure and are less invasive and risky than traditional open surgeries.

Get Care

Trust NewYork-Presbyterian for Surgical Weight Loss Therapies

If you’re at least 80 pounds over a healthy weight threshold and wish to explore the possibilities of surgical weight loss procedures, schedule an appointment with NewYork-Presbyterian to talk to a doctor. During your appointment, you’ll learn more about the best available options to lose weight that fit your specific situation, such as metabolic and bariatric surgeries.