Roux-en-Y gastric bypass
How the surgery works
The operation works in two main ways: by making your stomach smaller and by changing the route food takes through your digestive system.
The surgeon creates a small pouch at the top of your stomach. This pouch holds the food you eat and means you feel full after eating a smaller amount. The surgeon then divides your small intestine approximately 75–150cm from the top and connects the lower part of the intestine to the new stomach pouch. Food therefore passes directly from the pouch into the lower part of your small intestine.
The remaining part of your stomach stays inside your body, although food no longer passes through it. It continues to produce digestive juices, which mix with food further down the intestine.
The amount of food you can eat is reduced, so you should feel full more quickly and stay full for longer. The surgery also affects hormones involved in hunger and fullness.
You will still absorb most nutrients from your food, although your body may absorb less protein, vitamins and minerals than before surgery.
What you need to do after surgery
You will need to:
- follow the eating habits and post-surgery diet recommended by your bariatric team
- take vitamin and mineral supplements every day for the rest of your life
- have regular blood tests to check for nutritional deficiencies
Following the recommended diet can also help reduce problems such as nausea and vomiting.
Expected weight loss
Most people lose weight quickly during the first year following gastric bypass surgery. You will usually reach your lowest weight around 12–18 months after surgery.
On average, people lose around 65–75% of their excess body weight, equivalent to approximately 25–35% of their total body weight. The amount of weight lost varies from person to person.
Following the dietary, activity and lifestyle advice recommended by your healthcare team can help you achieve and maintain the best possible result.
Advantages
Possible advantages include:
- the amount of food you can eat is reduced
- you are likely to feel full more quickly and stay full for longer
- weight loss begins soon after surgery
- weight loss tends to be relatively rapid
- average weight loss is greater than with some other procedures
- gastric bypass can be particularly effective at improving blood glucose control and reducing medication requirements for some people with type 2 diabetes
Disadvantages and possible side effects
These can include:
- lifelong vitamin and mineral supplements
- an increased risk of nutritional deficiencies, including vitamin B12, iron and calcium deficiency
- temporary hair thinning during periods of rapid weight loss
- gallstones caused by rapid weight loss, which may occasionally require surgery
- nausea and vomiting, particularly during the first few days after surgery or if you eat too quickly or too much