Gastric Bypass Surgery (Roux-En-Y)

What is a gastric bypass (roux-en-y)?

Gastric bypass is also known as Roux-en-Y Gastric Bypass (RYGB) — pronounced "roo-en-why". It is a type of weight loss surgery that reduces the size of your stomach to a small pouch by clipping off a section of it.

This small pouch is directly attached to the small intestine, bypassing the rest of the stomach and the upper end of the small intestine. This surgery not only reduces food intake but also limits the absorption of calories and fats by the body.

Gastric bypass is a surgical intervention for obesity. It is done when diet and exercise are not effective or when your weight causes serious health problems. Although difficult, a gastric bypass procedure can be reversed.

Differences between Roux-en-y and vertical sleeve gastrectomy

Vertical sleeve gastrectomy is another type of bariatric surgery that permanently reduces the size of your stomach to limit your food intake. The table below highlights the key differences between these procedures:

Gastric bypass (Roux-en Y) Vertical sleeve gastrectomy
Part of the stomach is clipped off so a small pouch remains. Part of the stomach is permanently removed, leaving a small tube-shaped pouch that is directly connected to the small intestine.
This new stomach pouch is attached to a section of the small intestine, bypassing the rest of the stomach and the first part of the small intestine. No other changes are made to the digestive system.

Your doctor will advise the best course of treatment for you, depending on your current health and condition.

Why do you need a gastric bypass?

Gastric bypass is known to produce:

  • 60% – 80% excess weight loss in the short term.
  • More than 50% excess weight loss in the long term.
  • Weight loss within a shorter time frame compared with other surgical procedures.
  • Clear resolution of obesity-related health problems.

In general, all types of bariatric surgery including gastric bypass can successfully manage your weight and greatly improve obesity-associated disorders, such as:

To qualify for gastric bypass, your body mass index (BMI) must be:

  • More than 32.5, and you must have an obesity-associated disorder such as Type 2 diabetes.
  • More than 37.5.

Gastric bypass surgery can help you to enjoy a better quality of life and a longer lifespan. It can also help to prevent future health problems. However, you must be willing to make lifelong lifestyle changes to benefit from weight loss surgery.

Who should not undergo a gastric bypass?

A gastric bypass may not be suitable for everyone who is severely overweight. You need to meet certain medical requirements to qualify for weight-loss surgery. Your doctor will determine whether:

  • You are a suitable candidate.
  • Gastric bypass is the best type of weight loss surgery for you.

When compared to other types of weight loss surgery, gastric bypass carries the following disadvantages:

  • Longer recovery period.
  • Slightly higher risk of complications, which can be avoided with proper care.
  • Intestinal bypass results in lower absorption of nutrients and vitamins, which can lead to deficiencies particularly in vitamin B12, iron, calcium and folate. You will need to take vitamins for life.
  • Higher risk of dumping syndrome, which causes diarrhoea, nausea and vomiting.

What are the risks and complications of a gastric bypass?

Weight loss surgery is considered safe in general. There are some inherent risks as with all major surgery, such as:

  • Infection
  • Excessive bleeding
  • Adverse reactions to anaesthesia
  • Blood clots and deep vein thrombosis
  • Intestinal leaks in staple line or joints
  • Lung or breathing problems

Specifically, risks and complications related to gastric bypass include:

  • Higher risk of nutritional deficiencies.
  • Increased sensitivity to alcohol.
  • Stomach ulcers.
  • Bowel obstruction, which is when your small or large intestine gets blocked and prevents fluids and digested food from passing through. Food, fluids, gastric acids and gas can build up behind the blockage and potentially cause your intestine to rupture.
  • Stomach perforation, which is when a hole forms all the way through your stomach, large bowel, or small intestine.

Why choose Mount Elizabeth Hospitals?

At Mount Elizabeth Hospitals in Singapore, we are committed to giving you comprehensive care in a private and personalised setting.

Our multidisciplinary team of surgeons, nurses and dietitians are here to guide you through the entire gastric bypass surgery process from pre-surgery diet and exercise preparation to post-op recovery.

Our general surgeons

Mount Elizabeth's panel of general surgeons are skilled and experienced in performing gastric bypass surgery to lower the risks of obesity-related disorders. As much as possible, our surgeons will use laparoscopic procedures to promote faster recovery.

They are supported by a team of dietitians and nurses who will work closely with you for a smooth recovery and long-lasting change in your health.

This page has been reviewed by our medical content reviewers.

Need help?

For enquiries, please call
+65 6250 0000 (Orchard) or +65 6898 6898 (Novena)

For appointment bookings, please WhatsApp
+65 8111 7777 (Orchard) or +65 8111 5777 (Novena)