Overview

Gastric bypass, also called Roux-en-Y (roo-en-wy) gastric bypass, is a type of weight-loss surgery that involves creating a small pouch from the stomach and connecting the newly created pouch directly to the small intestine. After gastric bypass, swallowed food will go into this small pouch of stomach and then directly into the small intestine, thereby bypassing most of your stomach and the first section of your small intestine.

Gastric bypass is one of the most commonly performed types of bariatric surgery. Gastric bypass is done when diet and exercise haven't worked or when you have serious health problems because of your weight.

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Why it's done

Gastric bypass 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
  • High cholesterol
  • Obstructive sleep apnea
  • Type 2 diabetes
  • Stroke
  • Cancer
  • Infertility

Gastric bypass is 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.

Check with your health insurance plan or your regional Medicare or Medicaid office to find out if your policy covers weight-loss surgery.

Risks

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 are similar to any abdominal surgery and can include:

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

Longer term risks and complications of gastric bypass can include:

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

Rarely, complications of gastric bypass can be fatal.

How you prepare

In the weeks leading up to your surgery, you may be required to start a physical activity program and to stop any tobacco use.

Right before your procedure, you may have restrictions on eating and drinking and which medications you can take.

Now is a good time to plan ahead for your recovery after surgery. For instance, arrange for help at home if you think you'll need it.

What you can expect

Gastric bypass surgery is done in the hospital. Depending on your recovery, your hospital stay is typically one to two days but may last longer.

During the procedure

You will be given general anesthesia before your surgery begins. Anesthesia is medicine that keeps you asleep and comfortable during surgery.

The specifics of your gastric bypass depend on your individual situation and the doctor's practices. Some surgeries are done with traditional large (open) incisions in your abdomen. However, most are performed laparoscopically, which involves inserting instruments through multiple small incisions in the abdomen.

After making the incisions with the open or laparoscopic technique, 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.

Surgery usually takes a few hours. After surgery, you awaken in a recovery room, where medical staff monitors you for any complications.

After the procedure

Immediately after gastric bypass surgery, you may have liquids but no solid food as your stomach and intestines begin to heal. You'll then follow a special diet plan that changes slowly from liquids to pureed foods. After that, you can eat soft foods, then move on to firmer foods as your body is able to tolerate them.

You may have many restrictions or limits on how much and what you can eat and drink. Your doctor will recommend you take vitamin and mineral supplements after surgery, including a multivitamin with iron, calcium and vitamin B-12.

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, bloodwork 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, including:

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

Video: Roux-en-Y gastric bypass

In Roux-en-Y gastric bypass, the surgeon creates a small pouch at the top of the stomach. The pouch is the only part of the stomach that receives food. This greatly limits the amount that you can comfortably eat and drink at one time. The small intestine is then cut a short distance below the main stomach and connected to the new pouch. Food flows directly from the pouch into this part of the intestine. The main part of the stomach, however, continues to make digestive juices. The portion of the intestine still attached to the main stomach is reattached farther down. This allows the digestive juices to flow to the small intestine. Because food now bypasses a portion of the small intestine, fewer nutrients and calories are absorbed.

Results

Gastric bypass 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 about 70%, or even more, of your excess weight within two years.

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

  • Gastroesophageal reflux disease
  • Heart disease
  • High blood pressure
  • High cholesterol
  • Obstructive sleep apnea
  • Type 2 diabetes
  • Stroke
  • Infertility

Gastric bypass 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

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

It's important to keep all of your scheduled follow-up appointments after weight-loss surgery so that your doctor can monitor your progress. If you notice that you aren't losing weight or you develop complications after your surgery, see your doctor immediately.

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Gastric bypass (Roux-en-Y) care at Mayo Clinic

Oct. 17, 2020
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