How does the Roux-en-Y gastric bypass work? - Obesity Surgery Guide

Roux-en-Y gastric bypass surgery is carried out whilst the patient is under a general anaesthetic. The surgery is known as both restrictive and malabsorptive due to how it works. The restrictive aspect of the Roux-en-Y bypass is due to the reduction of the stomach size to make you feel fuller after less food. The malabsorptive aspect is thanks to the bypass of the small intestine and stomach to theoretically decrease the number of calories absorbed from any meals consumed.

The Roux-en-Y gastric bypass procedure does not remove any parts of the stomach to achieve its effects. Instead, the surgery involves physically dividing the small intestine and stomach. This is rather demanding and requires an experience surgeon. However, as the surgery has been performed so many times, it is now considered to be routine and safe for those who wish to undergo it.

The Procedure

Your surgeon will begin by dividing your stomach into two different sections. The upper segment will be smaller and these two sections are sealed using staples to create isolated compartments. The upper compartment is known as a pouch, which is the receiver of any food you consume. The segregated lower stomach no longer obtained food.

The next step involves your surgeon connecting the pouch to the lower end of your small intestine. This is done so that when you eat, the food also doesn't come into contact with the small intestine as well as the lower stomach. The surgeon achieves this by stapling the small intestine to reduce its size and then attaching the pouch to it. The opening between the stomach and intestine is kept small to restrict the amount of food that can physically pass through it.

The final stage of the procedure involves your surgeon connecting the other end of your small intestine with your lower bowel. This creates a 'Y' shape, hence the name Roux-en-Y gastric bypass.

How does this actually work to help weight loss?

This surgery works as it allows the food to move directly between the stomach and small intestine, whilst avoiding the upper part of the intestine, known as the duodenum. Furthermore, the other component of the 'Y' shape contains enzymes and digestive juices. These are able to travel down into the intestine where they will meet the food at the junction. Here, the enzymes, digestive juices and food combine to all full food breakdown and absorption.

The actual outcome achieved from the Roux-en-Y bypass surgery is that the regular absorption of food is disrupted. This allows for fewer calories to be absorbed, which subsequently results in weight loss.

How much weight can I expect to lose?

The amount of weight that you may lose following the Roux-en-Y gastric bypass procedure is not certain. The results vary between individuals depending on factors such as initial weight, food intake etc. However, a study conducted in 2009 showed that approximately 70% of surplus weight was lost by Roux-en-Y patients within just 19 months of the surgery.

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