Bariatric Surgery

Treating Obesity with Surgery

Obesity is a chronic disorder that can lead to other health problems such as diabetes, high blood pressure, and obstructive sleep apnea. Because obesity can affect many organs, it may be difficult to treat. When other medically supervised methods of weight loss have failed, weight-loss surgery can be an effective way to lose weight and maintain that weight loss.

To be considered for weight-loss surgery, you must meet the following qualifications:

  • A body mass index (BMI) of 40 or higher (20 to 25 is considered normal). BMI is a calculated by dividing your weight in kilograms by height in meters squared. See the BMI tool and BMI chart.
  • A body mass index (BMI) between 35 and 40 and have an obesity-related condition such as cardiovascular disease, diabetes mellitus, hypertension or severe sleep apnea.

The UCSF Bariatric Surgery Center has been performing surgical weight-loss procedures since 1996. There are three weight-loss procedures offered at UCSF and each is considered "restrictive," which means the procedure limits the amount of food you can consume at one time.

During your initial visit to the Bariatric Surgery Center, one of our bariatric surgeons will discuss in detail the different operations, explain the risks and benefits of each, and determine the procedure that's best for you.

When considering weight-loss surgery, it is important to understand that success in maintaining weight loss is dependent on your commitment to making major diet and lifestyle changes. Surgery is a powerful tool meant to assist in weight loss. Your participation at home and through our bariatric program is important in achieving your weight loss goals, and in maintaining weight loss so you can be successful many years after surgery.

Surgical Procedures Offered

Roux-en-Y Gastric Bypass

Gastric bypass is the current "gold standard" procedure for weight-loss surgery, according to the American Society for Bariatric Surgery and the National Institutes of Health (NIH). This procedure bypasses most of the stomach and the first part of the samll intestine.

A small stomach pouch is created using a surgical stapler. The remainder of the stomach is not removed, but is stapled shut. The pouch restricts food intake so you're only able to eat small amounts of food at one time. The small intestine is divided and one end is raised and attached to the stomach pouch in a procedure called a gastrojejunostomy. The other end of the small intestine, still connected to the stomach remnant, is reconnected to another portion of the intestinal tract in a procedure called a jejunojejunostomy.


  • Average weight loss is 70 to 80 percent of your excess body weight.
  • Average weight loss is greater than the average achieved by sleeve gastrectomy and gastric band surgery.
  • Studies show that gastric bypass surgery alters the metabolism of carbohydrates and increases insulin sensitivity, often eliminating the need for diabetes medications.
  • Medical conditions related to obesity — such as acid reflux, high cholesterol and high blood pressure, and sleep apnea — are improved or eliminated after surgery.


  • Absorption of iron and calcium is decreased because the duodenum, or first part of the small intestine, is bypassed. Deficiencies of these minerals can lead to anemia and bone disease so you must take vitamins and other supplements.
  • Vitamin B12 supplements must be taken to prevent a deficiency.
  • A condition known as "dumping syndrome" can occur after eating too quickly or after eating foods high in refined sugars or carbohydrates or high in fat. Symptoms include nausea, skaing, sweating, light headedness, flushing and fast heart rate.
  • In some cases, the procedure's effectiveness may lessen if the stomach pouch is stretched or if it is initially left larger than 15 to 30 cubic centimeters.
  • The bypassed portion of the stomach, duodenum and segments of the small intestine cannot be easily visualized using X-ray or endoscopy if problems such as ulcers, bleeding or cancer occur.

Adjustable Gastric Band

In this procedure, a band is placed around the upper part of your stomach, creating a small pouch that restricts food intake and creates a sense of being full after very small meals. The band can be adjusted to make the pouch outlet smaller or larger by injecting fluid into the band. A small "port" is implanted beneath the skin, and is connected to a catheter for the flow of fluid that adjusts the band.


  • No stapling, cutting or removal of stomach tissue.
  • Slightly shorter recovery period.
  • Band is adjustable, allowing your surgeon to control the size of your pouch outlet.
  • If the band is removed, the stomach usually returns to its original form.


  • On average, less weight loss than sleeve gastrectomy or gastric bypass.
  • Risk of band sllippage or erosion, which requires an additional operation to remove the band.
  • Risk of mechanical failure, such as port or tube leaking.
  • Follow-up adjustments required to the band and must be made by inserting a needle into the port.

Sleeve Gastrectomy

This operation involves only your stomach. A small sleeve, or narrow pouch, is created using a surgical stapler to separate the stomach. After the sleeve is created, the rest of the stomach — about two-thirds of the stomach — is removed. The sleeve creates a feeling of being full faster and decreases appetite. Only small amounts of food can pass through the sleeve at one time.


  • No foreign body implanted.
  • No rerouting of the intestinal tract.
  • Average weight loss is greater than gastric band, but slightly less than gastric bypass.


  • Less long-term data available on the outcomes of sleeve gastrectomy.Risk of leaking at the staple line of the stomach.

Laparoscopic or Minimally Invasive Surgery

Laparoscopic, or minimally invasive, surgery is a technique that involves a small video camera inserted into the abdomen. through several small incisions. The surgeon views images generated by the camera in the abdomen on a video monitor in the operating room.

The American Society for Bariatric Surgery recommends that laparoscopic weight-loss surgery is performed only by surgeons experienced in both laparoscopic and open bariatric procedures. At the UCSF Bariatric Surgery Center, our experts are trained in the advanced techniques required to perform laparoscopic procedures.

Laparoscopic surgery is considered minimally invasive because it replaces the need for one long incision to open the abdomen. Studies show that patients who undergp laparoscopic weight-loss surgery experience less pain after surgery, resulting in easier breathing and lung function.

Other benefits of laparoscopy are fewer wound complications, such as infection or hernia. In addition, patients typically return more quickly to their normal activities after surgery.

More Information

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Reviewed by health care specialists at UCSF Medical Center.

Related Information

UCSF Clinics & Centers

Bariatric Surgery Center
400 Parnassus Ave., Sixth Floor, Reception Desk 6S
San Francisco, CA 94143-0338
Phone (existing patients):
(415) 353-2161
Phone (new patients):
(415) 353-2804
Fax: (415) 353-2505

Condition Information

Patient Experiences

Our Experts

Jonathan Carter
Dr. Jonathan Carter,
bariatric and general surgeon
John P. Cello
Dr. John P. Cello,
Mary Ellen DiPaola
Mary Ellen DiPaola,
dietitian and diabetes educator
Nicole Yvonne Nguyen
Andrew Posselt
Dr. Andrew Posselt,
bariatric and transplant surgeon
Stanley Rogers
Dr. Stanley Rogers,
bariatric and laparoscopic surgeon