Gastric Bypass

Roux-en-y gastric bypass changes the stomach and small intestine to cause weight loss by:

  • Restricting food intake: creates a small pouch to serve as the stomach, so you cannot eat as much as before
  • Making the body unable to absorb as many calories from the food: bypasses the first part of the small intestine, where many of the calories from food are usually absorbed

Reasons for the procedure

The surgery treats severe obesity. A calculation called body mass index (BMI) is used to determine how overweight or obese you are. A normal BMI is 18.5-25. Roux-en-Y gastric bypass is a weight loss option for people with:

  • BMI greater than 40
  • BMI 35-39.9 and a life-threatening condition or severe physical limitations that affect employment, movement and family life

The success of gastric bypass surgery depends on your commitment to lifelong health habits. If lifestyle changes are made and maintained, the benefits of bariatric surgery include:

  • Long-term weight reduction
  • Improvement in many obesity-related conditions
  • Improved movement and stamina
  • Enhanced mood, self-esteem and quality of life

Advantages of gastric bypass:

  • Average weight loss is 75% of excess weight.
  • Weight loss occurs rapidly with most of the excess weight being lost in the first 12 months.
  • 96% of certain associated health conditions (back pain, sleep apnea, high blood pressure, diabetes and depression) are improved.
  • Early and late complication rates are reasonably low, and operative mortality ranges from 0.2 percent to 1 percent.
  • Patients return to eating a normal balanced diet but much smaller quantities.

Disadvantages of gastric bypass:

  • Because the duodenum is bypassed, poor absorption of iron and calcium can result in the lowering of total body iron and a predisposition to iron deficiency anemia. This is a particular concern for patients who experience chronic blood loss during excessive menstrual flow or bleeding hemorrhoids. Women, already at risk for osteoporosis that can occur after menopause, should be aware of the potential for heightened bone calcium loss.
  • Bypassing the duodenum has caused metabolic bone disease in some patients, resulting in bone pain, loss of height, humped back and fractures of the ribs and hip bones.

All of the deficiencies mentioned above, however, can be managed through proper diet and vitamin supplements.

  • A chronic anaemia due to Vitamin B12 deficiency may occur. The problem can usually be managed with Vitamin B12 pills or injections.
  • A condition known as “dumping syndrome” can occur as the result of rapid emptying of stomach contents into the small intestine. This is sometimes triggered when too much sugar or large amounts of food are consumed. While generally not considered to be a serious risk to your health, the results can be extremely unpleasant and can include nausea, weakness, sweating, faintness, and on occasion,diarrhea after eating. Some patients are unable to eat any form of sweets after surgery.
  • In some cases, the effectiveness of the procedure may be reduced if the stomach pouch is stretched and/or if it is initially left larger than 15-30cc.

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 malignancy should occur.
Residual stomach capacity: 30-50 mL
Estimated weight loss: 60-70% EWL over 2 years
Operative time about 1-2 hrs.
Hospitalization usually 2-3 days

What to expect prior to procedure:

Before the procedure, you will likely have the following:

  • Thorough physical exam and review of medical history
  • Ongoing consultations with a registered dietitian
  • Mental health evaluation and counseling

Leading up to your procedure:

  • Talk to your doctor about your medications, herbs, and dietary supplements. You may be asked to stop taking some medications up to one week before the procedure, such as:
    • Anti-inflammatory drugs
    • Blood thinners
    • Antiplatelets
  • Do not start taking any new medications, herbs, or supplements without talking to your doctor.
  • Arrange for help at home as you recover.
  • You may be asked to take antibiotics before coming to the hospital.
  • You may be asked to take laxatives and/or enema to clear your intestines.
  • The night before your surgery, eat a light meal. Do not eat or drink anything after midnight unless told otherwise by your doctor.
  • Shower or bathe the morning of your surgery.


General anesthesia will be used. You will be asleep.

Description of procedure

Gastric Bypass

To prepare you for surgery, an IV will be placed in your arm. You will receive fluids and medications through this line during the procedure. A breathing tube will be placed through your mouth and into your throat. This will help you breathe during surgery. You will also have a catheter placed in your bladder to drain urine.

5-6 small trocar incisions will be made to use the laparoscope. Surgical staples will be used to create a small pouch at the top of your stomach. This pouch, which can hold about one cup of food, will be your new, smaller stomach. A normal stomach can hold 4-6 cups of food.

Next, the small intestine will be cut and attached to the new pouch. With the intestinal bypass, food will now move from the new stomach pouch to the middle section of the small intestine. It will skip the lower stomach and the upper section of the small intestine.

Finally, the upper section of the small intestine will be attached to the middle section of the small intestine. This will allow fluid that the lower stomach makes to move down the upper section of the small intestine and into the middle section.

When the bypass is completed, the incisions will be closed with staples or stitches.

After the procedure

You will be taken to the recovery area for monitoring. You will also be given pain medication.

How long will it take?

About two hours.

How much will it hurt?

Anesthesia will prevent pain during surgery. Pain and discomfort after the procedure can be managed with medications.

Average hospital stay

The usual length of stay is 2-3 days. Your doctor may choose to keep you longer if complications arise.

Post-procedure care at the hospital

While you are recovering at the hospital, you may receive the following care:

  • Pain medication will be given as needed.
  • Your diet:
    • On the day of surgery: You will not be given food or drink.
    • On the day after surgery: You will have an X-ray to check for leaks from the stomach pouch. For this test, you will drink a special liquid while X-rays are taken.
    • If the upper GI X-ray is normal: You will be given 30 milliliters (mL) of liquids every 20 minutes.
    • If leaks are found: You will receive nutrition through an IV until the leaks are fixed.
    • On the second day after surgery: You will take 1-2 tablespoons of pureed food or 1-2 ounces of liquids every 20 minutes.

While in the hospital, you may be asked to do the following:

  • Use an incentive spirometer to help you take deep breaths. This helps prevent lung problems.
  • Wear elastic surgical stockings or boots to promote blood flow in your legs.
  • Get up and walk daily.

Preventing infection

During your stay, the hospital staff will take steps to reduce your chance of infection, such as:

  • Washing their hands
  • Wearing gloves or masks
  • Keeping your incisions covered

At home

Be sure to follow your doctor’s instructions. You will need to practice lifelong healthy eating and exercising habits. Keep in mind after your surgery:

  • Ask your doctor about when it is safe to shower, bathe or soak in water.
  • You may be out of work for 2-6 weeks after gastric bypass surgery.
  • Do not drive or lift anything heavy until your doctor tells you it is safe. This may be up two weeks or more.
  • Walk as soon as possible, with a goal of exercising daily.
  • You may have emotional changes after this surgery. Your doctor may refer you to a therapist.
  • You will meet regularly with your healthcare team for monitoring and support.

Your new stomach is the size of a small egg. It is slow to empty, causing you to feel full quickly. Therefore, you need to eat very small amounts and eat very slowly:

  • You will begin with 4-6 meals per day. A meal is two ounces of food.
  • For the first 4-6 weeks after surgery, all food must be pureed.
  • When you move to solid foods, they must be chewed well.
  • When making food choices, you will need to consume enough protein.
  • Avoid sweets and fatty foods.
  • Eating too much or too quickly can cause vomiting or intense pain under your breastbone. Most people quickly learn how much food they can eat.

Call your doctor

Call your doctor if any of these occur:

  • Signs of infection, including fever and chills
  • Redness, swelling, increasing pain, excessive bleeding or discharge from the incision site
  • Persistent cough, shortness of breath or chest pain
  • Worsening of abdominal pain
  • Blood in stools
  • Pain, burning, urgency or frequency of urination, or persistent bleeding in the urine
  • Persistent nausea and/or vomiting
  • Pain and/or swelling in your feet, calves, or legs; sudden shortness of breath or chest pain
  • New or worsening symptoms
  • universite de montreal
  • American Society for Metabolic and Bariatric Surgery
  • mount sinai
  • Prince Mohamed bin Abdulaziz Hospital
  • International Federation for the Surgery of Obesity and Metabolic Disorders
  • King Khalid University Hospital
  • American Association of Bariatric Counselors
  • Society of American Gastrointestinal and Endoscopic Surgeons
  • mc gill
  • Society for Surgery of the Alimentary Tract
  • surgery for obesity and related diseases
  • The International College of Surgeons (ICS)
  • juniper online journal of case studies
  • Obesity Medicine
  • journal of universal surgery
  • american journal of innovative research & applied sciences
  • asian council of science editors
  • medcrave
  • insight knowledge
  • American College of Surgeons
  • Specialized Medical Center
  • Saudi German Hospitals