Roux-en-y gastric bypass: benefits, cost, side effects

last updated: Oct 29, 2021

6 min read

The United States currently ranks second in the world for the highest levels of obesity. According to the Centers for Disease Control (CDC), more than 93 million adults in the U.S. classify as overweight by body mass index (BMI) standards (Mitchell, 2021).

Excess body weight is a complex condition with many contributing factors, some of which are outside a person’s control (like genetics). Still, having this condition can increase your risk of many different illnesses, such as diabetes, heart disease, hypertension, arthritis, and cancer. It’s no wonder that medical researchers have been hard at work to come up with new ways to prevent and treat this chronic condition (Mitchell, 2021).

One way that healthcare providers have found to treat obesity is with roux-en-y gastric bypass surgery. Let’s look at this common weight loss procedure and how it might benefit you.

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What is roux-en-y gastric bypass?

Roux-en-y gastric bypass (RYGB) is a type of weight loss surgery that changes how food flows through your stomach and intestines. The stomach is divided into a small pouch and attached to a part of the small intestine further down than usual. The result of having a smaller stomach is that you can only eat a small amount of food at one time, and the food passes through your gastrointestinal (GI) tract more quickly. This means that fewer calories are absorbed, allowing you to lose excess weight (Stahl, 2021).

The RYGB procedure was first introduced in 1966 and has grown in popularity since then. It’s now the second most popular type of bariatric (weight loss) surgery in the United States (Mitchell, 2021).

Other ways researchers think that roux-en-y gastric bypass helps you lose weight include changing the bacteria levels in your GI tract, the levels of bile acids produced, and the amount of energy your body spends digesting. Researchers aren’t entirely sure how these changes lead to weight loss, but they are continuing to study them (Stahl, 2021).

How does laparoscopic roux-en-y gastric bypass work?

Roux-en-y gastric bypass surgery is usually performed laparoscopically, meaning it’s performed using cameras and tools inserted through small incisions in your abdomen. The exact technique varies between surgeons but typically includes the following steps (Mitchell, 2021; Stahl, 2021):

  1. Preparation: Under general anesthesia, the surgeon inserts tools into the abdomen that allow them to insert the laparoscope (camera) and other surgical instruments. Carbon dioxide is used to blow the abdomen up slightly like a balloon. This makes it easier to perform the surgery.

  2. Stomach pouch creation: The surgeon divides part of the stomach and makes a new pouch to hold food and fluids. This new stomach is much smaller than before. It only contains around 20 to 30 ml—two-thirds to one ounce—of volume.

  3. Biliopancreatic limb creation: The surgeon then connects the rest of the stomach, liver, pancreas, and the first portion of the small intestines into something called a biliopancreatic limb. This lets bile and digestive enzymes join your food in the intestines so that you can digest it. This also keeps the contents of your GI tract flowing in the right direction.

  4. Connecting the stomach pouch: The new stomach pouch is attached to the small intestine further down than it was before. This new path bypasses some of the small intestine and means fewer nutrients get absorbed. 

  5. Leak test: The procedure is almost complete, and the surgeon checks all of the new connections to make sure they are secure without any leaks. The new stomach pouch is filled with air while the outside is covered in saline (saltwater). Any leaks will show as air bubbles.

  6. Aftercare: Once the surgeon is sure there are no leaks, they’ll remove the carbon dioxide and all of the surgical instruments. They’ll then close the incisions and bring you to the post-anesthesia unit to wake up (Stahl, 2021).

How long you stay in the hospital after surgery depends on your medical conditions and how quickly you progress immediately after the surgery. Studies show that an overnight stay is the safest option for most patients. However, some patients are well enough to go home the same day (Mitchell, 2021).

You will have several follow-up appointments with your surgeon and with your nutritionist after your bariatric procedure.

What are the benefits of roux-en-y gastric bypass?

Research shows that bariatric surgeries such as roux-en-y gastric bypass provide greater and longer-lasting weight loss than medications for weight loss. Health conditions caused by chronic obesity might be improved or even eliminated. This can help you live a longer, healthier life (Tirthani, 2021).

RYGB helps you eat less food, feel fuller sooner, and change the way your body responds to hormones in your gut (Tirthani, 2021).

Leptin is a hormone made by the fat cells in your body. Its primary purpose is to control when your body feels hungry and how it stores fat. In obesity, your body doesn’t respond to leptin as well, and the levels in your body increase to compensate for this. This means you have trouble feeling full after you eat. Roux-en-y gastric bypass can help your body respond better to leptin, so you aren’t as hungry (Conner, 2021).

When you have excess weight, your body can become resistant to insulin. This makes your blood sugar levels go up, often causing diabetes. All types of weight loss surgery can improve your sensitivity to insulin, often within a few days after surgery. This can stop or even reverse the progression of type 2 diabetes (Conner, 2021).

Long-term studies have shown similar outcomes and complication rates for all participants, no matter what type of weight loss surgery they have (Conner, 2021).

Are there any side effects or risks from roux-en-Y?

Roux-en-y gastric bypass is one of the most common operations in the U.S., but any surgery can cause complications or side effects. This surgery won’t be the right choice for everyone.

Weight loss surgery isn’t appropriate for people with the following conditions (Mitchell, 2021):

  • Current pregnancy

  • Active cancer

  • Severe kidney or heart disease

  • Cirrhosis of the liver

If you have any of the following conditions, you might still be a candidate for RYGB, but your surgeon will have to assess your health status. These include (Mitchell, 2021):

  • Crohn’s disease

  • Severe mental health problems

  • A history of addiction

  • Uncontrolled high blood pressure

  • Intellectual disability

  • Seizure disorder

Having roux-en-y surgery will affect the way that your body absorbs food and medications. This means you might not absorb your medications as well as you used to. Your healthcare provider might have to adjust your dosages. You might also develop vitamin or mineral deficiencies and need to take supplements (Mitchell, 2021; Seeras, 2021).

Other possible complications from surgery include (Seeras, 2021):

  • Narrowing of your GI tract

  • Ulcers

  • Stones in your gallbladder

  • Hernias

  • Food moving too quickly through your GI tract (called dumping syndrome)

To maintain long-term weight loss, you will still need to make lifestyle changes and engage in regular physical activity.  Since the size of the stomach is significantly reduced, you will only be able to eat small meals. If you eat too much at once, you might vomit. In severe cases, the small stomach pouch can break open, and you will need surgery to fix it.

How to talk to your provider about weight loss surgery

If you’re interested in a roux-en-y gastric bypass, you’ll need to discuss it with your healthcare provider and get a referral to a surgeon who performs weight loss surgeries. You’ll also need to talk with your health insurance company to see if they provide benefits for weight loss surgery and how much they cover.

Your surgeon will tell you if you are a good candidate for weight loss surgery. Usually, the criteria for RYGB include having a body mass index (BMI) of 40 or more (also known as morbid obesity). You might also qualify if you have a BMI of 35 or more and have a medical problem that could be helped by losing weight (Stahl, 2021).

Many centers that perform weight loss surgery have special programs to guide you through getting ready for surgery and getting the procedure covered by your insurance company. You’ll work with a treatment team made of multiple types of healthcare professionals to make sure that you’re mentally and physically ready for surgery (Benalcazar, 2021).

The process of getting approved for weight reduction surgery often takes at least six months to a year and will involve several different types of evaluations to make sure that you’re ready for surgery. These might include (Benalcazar, 2021):

  • Mental health evaluation

  • Meeting with a nutritionist

  • Following a pre-surgery diet and exercise plan

  • Getting medically cleared for surgery

  • Screening for heart disease or sleep apnea

  • Abdominal ultrasound

  • Blood work

Your healthcare provider might request other types of tests before performing a roux-en-y gastric bypass, depending on your specific health situation (Benalcazar, 2021).


If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.

How we reviewed this article

Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

Current version

October 29, 2021

Written by

Ellyn Vohnoutka, BSN, RN

Fact checked by

Steve Silvestro, MD

About the medical reviewer

Dr. Steve Silvestro is a board-certified pediatrician and Associate Director, Clinical Content & Education at Ro.

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