Gastric bypass and other weight-loss surgeries make changes to your digestive system to help you lose weight by limiting how much you can eat or by reducing the absorption of nutrients, or both. Gastric bypass and other weight-loss surgeries are done when diet and exercise haven't worked or when you have serious health problems because of your weight.

There are many types of weight-loss surgery, known collectively as bariatric surgery. Gastric bypass is one of the most common types of bariatric surgery in the United States. Many surgeons prefer gastric bypass surgery because it generally has fewer complications than do other weight-loss surgeries.

Still, all forms of weight-loss surgery, including gastric bypass, are major procedures that can pose serious risks and side effects. Also, you must make permanent healthy changes to your diet and get regular exercise to help ensure the long-term success of bariatric surgery.

Gastric bypass surgery is done to help you lose excess weight and reduce your risk of potentially life-threatening weight-related health problems, including:

  • Gastroesophageal reflux disease
  • Heart disease
  • High blood pressure
  • Severe sleep apnea
  • Type 2 diabetes
  • Stroke

Gastric bypass and other weight-loss surgeries are typically done only after you've tried to lose weight by improving your diet and exercise habits.

Who it's for

In general, gastric bypass and other weight-loss surgeries could be an option for you if:

  • Your body mass index (BMI) is 40 or higher (extreme obesity).
  • Your BMI is 35 to 39.9 (obesity), and you have a serious weight-related health problem, such as type 2 diabetes, high blood pressure or severe sleep apnea. In some cases, you may qualify for certain types of weight-loss surgery if your BMI is 30 to 34 and you have serious weight-related health problems.

But gastric bypass isn't for everyone who is severely overweight. You may need to meet certain medical guidelines to qualify for weight-loss surgery. You likely will have an extensive screening process to see if you qualify. You must also be willing to make permanent changes to lead a healthier lifestyle. You may be required to participate in long-term follow-up plans that include monitoring your nutrition, your lifestyle and behavior, and your medical conditions.

And keep in mind that bariatric surgery is expensive. Check with your health insurance plan or your regional Medicare or Medicaid office to find out if your policy covers such surgery.

As with any major surgery, gastric bypass and other weight-loss surgeries pose potential health risks, both in the short term and long term.

Risks associated with the surgical procedure can include:

  • Excessive bleeding
  • Infection
  • Adverse reactions to anesthesia
  • Blood clots
  • Lung or breathing problems
  • Leaks in your gastrointestinal system
  • Death (rare)

Longer term risks and complications of weight-loss surgery vary depending on the type of surgery. They can include:

  • Bowel obstruction
  • Dumping syndrome, causing diarrhea, nausea or vomiting
  • Gallstones
  • Hernias
  • Low blood sugar (hypoglycemia)
  • Malnutrition
  • Stomach perforation
  • Ulcers
  • Vomiting
  • Death (rare)

If you qualify for gastric bypass or other weight-loss surgeries, your health care team gives you instructions on how to prepare for your specific type of surgery. You may need to have various lab tests and exams before surgery. You may have restrictions on eating and drinking and which medications you can take. You may be required to start a physical activity program and to stop any tobacco use.

You may also need to prepare by planning ahead for your recovery after surgery. For instance, arrange for help at home if you think you'll need it.

Gastric bypass and other types of weight-loss surgery are done in the hospital. General anesthesia is used for weight-loss surgery. This means you're unconscious during the procedure.

The specifics of your surgery depend on your individual situation, the type of weight-loss surgery you have, and the hospital's or doctor's practices. Some weight-loss surgeries are done with traditional large, or open, incisions in your abdomen. Today, most types of bariatric surgery are performed laparoscopically. A laparoscope is a small, tubular instrument with a camera attached. The laparoscope is inserted through small incisions in the abdomen. The tiny camera on the tip of the laparoscope allows the surgeon to see and operate inside your abdomen without making the traditional large incisions. Laparoscopic surgery can make your recovery faster and shorter, but it's not suitable for everyone.

Surgery usually takes several hours. After surgery, you awaken in a recovery room, where medical staff monitors you for any complications. Your hospital stay may last from three to five days.

Types of bariatric surgery

Each type of bariatric surgery has pros and cons. Be sure to talk to your doctor about them. Here's a look at common types of bariatric surgery:

  • Roux-en-Y (roo-en-y). This is a type of gastric bypass surgery, and is the most common method of gastric bypass. This surgery is typically not reversible. It works by decreasing the amount of food you can eat at one sitting and reducing absorption of nutrients. The surgeon cuts across the top of your stomach, sealing it off from the rest of your stomach. The resulting pouch is about the size of a walnut and can hold only about an ounce of food. Normally, your stomach can hold about 3 pints of food. Then, the surgeon cuts the small intestine and sews part of it directly onto the pouch. Food then goes into this small pouch of stomach and then directly into the small intestine sewn to it. Food bypasses most of your stomach and the first section of your small intestine, and instead enters directly into the middle part of your small intestine.
  • Biliopancreatic diversion with duodenal switch. This is another type of gastric bypass surgery. In this complex, multipart procedure, about 80 percent of the stomach is removed. The valve that releases food to the small intestine (the pyloric valve) remains, along with a limited portion of the small intestine that normally connects to the stomach (duodenum). The surgery bypasses the majority of the intestine by connecting the end portion of the intestine to the duodenum near the stomach (duodenal switch and biliopancreatic diversion). This surgery both limits how much you can eat and reduces the absorption of nutrients. While it's very effective, it has more risks, including malnutrition and vitamin deficiencies. It's generally used for people who have a body mass index greater than 50.
  • Laparoscopic adjustable gastric banding (LAGB). In this weight-loss surgery, the surgeon positions an inflatable band around the uppermost part of the stomach. When the band is inflated, it compresses the stomach, acting like a belt that tightens. This separates the stomach into two parts, with a very small upper pouch that communicates with the rest of the stomach through a channel created by the band. The small upper pouch limits the amount of food you can eat. The band can be adjusted so that it restricts more or less food. Because of its relative simplicity, LAGB is one of more common weight-loss surgeries. However, it may lead to less weight loss than may other procedures, and you may need to have the band adjusted periodically.
  • Sleeve gastrectomy. A sleeve gastrectomy, also called a vertical sleeve gastrectomy, is a newer type of weight-loss surgery. The sleeve gastrectomy is actually the first part of the surgical process for a biliopancreatic diversion with duodenal switch. However, the sleeve gastrectomy portion of surgery may be all that's needed to lose sufficient weight — in some cases the second part, biliopancreatic diversion, isn't needed. With sleeve gastrectomy, the structure of your stomach is changed to be shaped like a tube, which restricts the amount of calories your body absorbs.

Which type of weight-loss surgery is best for you depends on your specific situation. Your surgeon will take many factors into account, including your body mass index, your eating habits, your health problems, any previous surgery and the risks of each procedure.

After gastric bypass

After gastric bypass and other types of weight-loss surgery, you generally won't be allowed to eat for one to two days so that your stomach and digestive system can heal. Then, you'll follow a specific diet for about 12 weeks. The diet begins with liquids only, then progresses to ground-up or soft foods, and finally to regular foods. You may have many restrictions or limits on how much and what you can eat and drink.

You'll also have frequent medical checkups to monitor your health in the first several months after weight-loss surgery. You may need laboratory testing, blood work and various exams.

You may experience changes as your body reacts to the rapid weight loss in the first three to six months after gastric bypass or other weight-loss surgery, including:

  • Body aches
  • Feeling tired, as if you have the flu
  • Feeling cold
  • Dry skin
  • Hair thinning and hair loss
  • Mood changes

Gastric bypass and other bariatric surgeries can provide long-term weight loss. The amount of weight you lose depends on your type of surgery and your change in lifestyle habits. It may be possible to lose half, or even more, of your excess weight within two years.

In addition to weight loss, gastric bypass surgery may improve or resolve conditions often related to being overweight, including:

  • Gastroesophageal reflux disease
  • Heart disease
  • High blood pressure
  • Severe sleep apnea
  • Type 2 diabetes
  • Stroke

Gastric bypass surgery can also improve your ability to perform routine daily activities, which could help improve your quality of life.

When weight-loss surgery doesn't work

Gastric bypass and other weight-loss surgeries don't always work as well as you might have hoped. For one thing, although rare, something during or after the procedure itself may go wrong. For instance, the adjustable band may fail to work properly. If a weight-loss procedure doesn't work right or stops working, you may not lose weight and you may develop serious health problems. Keep all of your scheduled follow-up appointments after weight-loss surgery. If you notice that you aren't losing weight or you develop complications, see your doctor immediately. Your weight loss can be monitored and factors potentially contributing to your lack of weight loss evaluated.

It's also possible to not lose enough weight or to regain weight after any type of weight-loss surgery, even if the procedure itself works correctly. This weight gain can happen if you don't follow the recommended lifestyle changes. To help avoid regaining weight, you must make permanent healthy changes in your diet and get regular physical activity and exercise. If you frequently snack on high-calorie foods, for instance, you may have inadequate weight loss.

  • Experience. Surgeons at all three Mayo Clinic locations perform more than 500 weight-loss surgeries each year.
  • Positive results. In a study of patients who had weight loss surgery at Mayo Clinic, 72 percent of people who were followed maintained long-term weight loss of 50 percent or more of excess body weight after three years. Only 10 percent of patients had complications following surgery.
  • Complex cases. Mayo Clinic specializes in repairing problems resulting from previous bariatric surgery, and performing bariatric surgery in patients with complicated medical histories who may not qualify for surgery at other institutions.
  • Minimally invasive approach. Mayo Clinic uses minimally invasive techniques for bariatric surgery whenever possible. This approach offers smaller incisions, less pain, shorter hospital stays and faster recovery than traditional open surgery.
  • Team approach. A team of medical experts, including endocrinologists, surgeons, dietitians and psychologists, helps identify candidates who could most benefit from surgery and works intensively with you before and after surgery to help achieve a long-lasting result. After the first year, follow-up care can be conducted by your hometown doctor, working closely with the Mayo team.

Mayo Clinic in Rochester, Minn., ranks No. 1 for digestive disorders in the U.S. News & World Report Best Hospitals rankings. Mayo Clinic in Scottsdale, Ariz., and Mayo Clinic in Jacksonville, Fla., are ranked among the Best Hospitals for digestive disorders by U.S. News & World Report. Mayo Clinic also ranks among the Best Children's Hospitals for digestive disorders.

Mayo Clinic works with hundreds of insurance companies and is an in-network provider for millions of people. Mayo Clinic requires a referral from a primary care provider before evaluation for bariatric surgery.

Telephone requests

U.S. patients


Bariatric Surgery Coordinator
Phone: 480-342-2869
Fax: 480-301-8918
8 a.m. to 5 p.m. Mountain Standard time, Monday through Friday


Bariatric Surgery Coordinator
Phone: 904-953-0708
Fax: 904-953-6586
8 a.m. to 5 p.m. Eastern time, Monday through Friday


Bariatric Surgery Appointments
Phone: 507-284-2111
Fax: 507-284-5745
8 a.m. to 5 p.m. Central time, Monday through Friday

International patients

Please refer to the international appointment section to request appointments via phone.

See information on patient services at the three Mayo Clinic locations, including transportation options and lodging.

Mayo Clinic in Arizona has performed bariatric surgery procedures since 2001. Medically supervised interventions comprise: nutrition therapy, behavior modification, pharmacotherapy and weight-loss surgery, including laparoscopic adjustable gastric band, Roux-en-y gastric bypass and sleeve gastrectomy. Minimally invasive surgery is the preferred approach. For out-of-state patients, we offer efficient, condensed scheduling. We will work with providers in your area to meet your needs.

Bariatric Program informational seminars

Mayo Clinic conducts regular informational seminars for people interested in learning more about the medical and surgical options available through the Mayo Clinic Bariatric Program. The interactive seminars, conducted by doctors and other members of the bariatric treatment team, include:

  • A description of Mayo Clinic's multidisciplinary program
  • Answers to questions about care and precertification
  • Details about the registration process

Seminars are free of charge and open to anyone considering bariatric surgery. Feel free to bring family and friends.

The Bariatric Program informational seminars are held on select Tuesday and Thursday evenings at Mayo Clinic Hospital, room 1-115 (across from the Gift Shop on the first floor). To register, or for questions, call the Central Appointment Office at 800-446-2279 (toll-free).

If you have questions about the bariatric program, call 480-342-2869 to speak with our bariatric representative. Or send an email to:

Treatment team

A team of specialists works together to develop bariatric treatment plans tailored to your needs. Your team can include experts in Endocrinology, General Surgery, Community Internal Medicine, Psychiatry and Psychology, Dietetics and other specialists, as needed.

Bariatric Surgery Support Group

The Bariatric Surgery Support Group meets on the third Saturday of each month, from 9 a.m. to noon.

Mayo Clinic's campus in Florida has a dedicated Bariatric Center to help people struggling with obesity gain control of their weight. The Mayo Clinic team has a combined experience of more than 75 years caring for bariatric surgery patients.

Treatment team

A team of specialists work together to develop bariatric treatment plans tailored to each person's needs. Your team can include bariatric specialists from Endocrinology, General Surgery, Psychiatry and Psychology, Community Internal Medicine, Dietetics and other specialties, as needed.


The evaluation process usually takes about three to eight months. It may be longer than eight months before the surgery due to insurance processing and scheduling. The preliminary evaluation for bariatric surgery in Florida can be completed in one day.

Physician referrals are not required but are encouraged to help ensure the best continuity of care possible for patients. To begin the appointment process, call the Bariatric Center program coordinator at 904-953-0708.

Bariatric Surgery Support Group

A Bariatric Surgery Support Group meets on the second Monday of each month.


Physician referrals are not required but are encouraged to help ensure the best continuity of care possible for patients.

To begin the appointment process, call the Bariatric Center program coordinator at 904-953-0708.

Mayo Clinic surgeons in Minnesota perform over 300 bariatric surgeries each year. Several surgeons at Mayo Clinic in Minnesota have particular expertise in repairing previously unsuccessful bariatric surgeries, as well as treating severely obese people. Bariatric surgery is available for adults and adolescents who meet certain criteria.

Mayo Clinic in Rochester, Minn., continues to be recognized as an American College of Surgeons Level 1 Accredited Bariatric Center, the highest level of accreditation in bariatric surgery. Because of this accreditation, Mayo Clinic in Rochester, Minn., has also met Medicare's facility standards for bariatric surgery. Bariatric surgery accreditation promotes standard benchmarks and supports continuous quality improvement.

Treatment team

The Mayo Clinic bariatric care team in Minnesota consists of experts from Endocrinology,  Dietetics, Psychiatry and Psychology, Gastroenterologic and General Surgery, and other specialists, as needed.

Information sessions

Mayo Clinic in Rochester holds a monthly bariatric surgery information session. The sessions are conducted by an endocrinologist, dietitian, psychologist, surgeon, and a bariatric surgery coordinator. There is no charge for the sessions and they are open to anyone who has questions about bariatric surgery. Information session schedule (PDF).


To begin the bariatric surgery process at Mayo Clinic in Minnesota, use one of the following contact options:

  • Bariatric Surgery Coordinator: Phone: 507-538-1565, 8 a.m. to 5 p.m. Central time, Monday through Friday or email:
  • Endocrinology: 507-284-1600, 8 a.m. to 5 p.m. Central time, Monday through Friday

The length of time from your initial appointment to the date of surgery is usually about six to nine months. Your preliminary evaluation at Mayo Clinic in Rochester may last two to three days. If you are some distance from Mayo Clinic, you may be referred to a care provider in your local area to complete a portion of the evaluation. Near the end of the evaluation, you will meet with a surgeon to decide how to proceed.

Cost estimates

For questions about the cost of bariatric surgery, call Mayo Clinic Estimating Service at 507-284-4024.

Mayo Clinic researchers are investigating advanced and minimally invasive treatment options for bariatric surgery.


See a list of publications by Mayo physicians on bariatric surgery on PubMed, a service of the National Library of Medicine.

Sept. 07, 2017