Gastric bypass surgery

Gastric bypass surgery is an operation to help you lose weight if you’re very overweight. The surgery makes your stomach smaller and bypasses part of your bowels (intestines). Losing weight can help to improve any weight-related health problems you have.

About gastric bypass surgery

In gastric bypass surgery, your surgeon will section off part of your stomach and connect it directly to your small bowel. Food you eat will then bypass most of your stomach and the first part of your small bowel. You’ll feel fuller after eating smaller amounts of food. Gastric bypass surgery also changes hormone signals, including GLP-1, that pass between your bowel and your brain, which control your appetite.

You may hear this operation called a ‘Roux-en-Y’. This is the name of the method surgeons most often use to do it.

Gastric bypass surgery can help you lose up to two-thirds of your excess weight. You’re likely to lose most weight in the first year after surgery. You should be able to keep most of this weight off long-term. But this will depend on sticking to some major changes to your lifestyle after the operation. For example, you’ll need to:

• change your diet – stop snacking and choose healthier options
• not drink too much alcohol
• take regular exercise

Your doctor will talk through these changes with you.

Uses of gastric bypass surgery

Your GP may refer you to a specialist team to discuss your options. This is called a weight management service and includes a surgeon, dietitian, and psychologist. They’ll assess you to see if gastric bypass surgery is right for you. They may suggest weight loss surgery if you:

• have a body mass index (BMI) of 40 or more
• have a BMI over 35, with or without a condition that could improve if you lose weight (for example, type 2 diabetes or high blood pressure)
• are fit enough to have an anaesthetic and surgery
• are committed to having long-term follow-up appointments
• commit to changing your lifestyle and diet after your operation
• are over 18 (although children may have this surgery in exceptional circumstances)

You can usually only have gastric bypass surgery if you’ve tried to lose weight in other ways and this hasn’t worked. If you don’t meet the criteria for NHS funding, you may be able to have gastric bypass surgery privately.

Preparation for gastric bypass surgery

Your hospital will let you know how to prepare for your operation.

If you smoke, you’ll be asked to stop at least six weeks before the operation. Smoking increases your risk of complications after surgery.

Your surgeon may ask you to eat a low-fat, low-carbohydrate diet for two weeks before gastric bypass surgery . This will help to shrink your liver, which will allow your surgeon better access to your stomach.

You have gastric bypass surgery under a general anaesthesia (GA), so you’ll be asleep during the operation. You won’t be able to eat or drink for some time before surgery. Your doctors will tell you what to do – it’s important to follow their advice.

Your surgeon will ask you to wear compression stockings after the operation. This will help to prevent blood clots forming in the veins in your legs (deep vein thrombosis). You may also have injections of an anti-clotting medicine.

Your surgeon will discuss with you what will happen before, during, and after gastric bypass surgery . If you’re unsure about anything, ask. It’s important that you feel fully informed, so you feel happy to give your consent for the operation to go ahead. You do this by signing a consent form.

Gastric bypass surgery

A gastric bypass operation usually takes around two hours. But this can vary between hospitals.

Most surgeons use keyhole (laparoscopic) surgery. This means your surgeon will make several small cuts in your tummy rather than one large cut. They’ll put small instruments through the cuts and guide them using a telescope with a camera. Your surgeon may start with keyhole surgery and switch to open surgery if needed, but this isn’t common.

During the operation, your surgeon will staple across the top of your stomach, to form a small pouch. They’ll make an opening in the pouch and connect it directly to your small bowel. Food passing through will then bypass the lower part of your stomach and the first part of your small bowel. Your surgeon will reconnect the first part of your small bowel further down. This means the juices from your stomach, pancreas, and liver can mix with the food so that you can absorb nutrients after gastric bypass surgery .

Your surgeon will close your cuts with stitches and cover them with a dressing.

Recovery following gastric bypass surgery

Everyone recovers at their own rate, but allow up to six weeks to recover fully from a gastric bypass operation.

You have to make major changes to your lifestyle and diet after gastric bypass surgery, as your stomach will be smaller. You have a liquid diet for the first couple of weeks after you get home. Then you move on to puréed, then mashed food. By six weeks after your operation, you should be able to have several small solid meals a day.

It can be difficult to drink enough. You need at least one and a half to two litres a day to stay healthy. Drink slowly and between meals or it will fill you up too much.

Make sure you get enough protein every day. If you don’t, it can affect your health. Your doctor is likely to suggest a low-fat, high protein diet.

It’s difficult to get enough vitamins and minerals from your diet after gastric bypass. So you’ll need to take a complete multivitamin supplement for the rest of your life. You may also have regular vitamin B12 injections. Your doctor will arrange regular blood tests to check you’re getting everything you need.

You’ll need to do more exercise and drink less alcohol too. This will help you to get the most from your gastric bypass operation, so you can lose excess weight and keep it off.

Losing weight after a gastric bypass is usually a positive thing. But you may find it hard to adapt to your lifestyle and appearance after the operation. Talk to your GP or surgeon if you’re struggling to cope. They may suggest a patient support group. There you can get advice from other people who have been through the same operation.

Side-effects of gastric bypass surgery

You may have some bruising around your wounds after a gastric bypass. But this shouldn’t last more than a week or two.

You may feel sick or even be sick after eating. This is because you’ll only be able to eat a small amount of food at a time. This should get better with time as you get used to eating smaller amounts.

You may get an unpleasant side-effect called dumping syndrome if you eat too many sugary foods. It can make you feel sweaty, sick and lightheaded. You may also feel very tired and have tummy pain and diarrhoea. Symptoms can come on 30 minutes to an hour after you eat (early dumping), or within three hours (late dumping). It may help to:

• eat smaller more frequent meals that are low in carbohydrates, especially sugar
• don’t drink during meals or for half an hour afterwards
• cut down or cut out dairy products
• rest for half an hour after eating

Ask your dietitian or doctor for more advice.

Complications of gastric bypass surgery

Gastric bypass complications can happen soon after surgery or some months later. Early complications happen within a month of surgery. They include bleeding or a leak from the stomach or bowel. This is most likely where the stomach has been stapled or your small bowel rejoined. If you have tummy or shoulder pain, see signs of blood when you’re sick, or your poo looks black like tar, contact your surgeon or hospital.

Later complications can include the following.

• Gallstones – this can happen to one in three people who have this type of operation.
• • An internal hernia – part of the small bowel can get twisted at the site of the operation, which causes pain and you might require emergency surgery.
• Stomach ulcer – you may have a medicine to reduce stomach acid to help prevent this. Ulcers are more common in smokers.
• • A stricture – this is narrowing of the join between your stomach pouch and small bowel. You may feel sick, or be sick.

If you have pain, sickness that doesn’t go away, or any other concerns after your gastric bypass surgery , contact your surgeon for advice.

These complications may sound frightening, but, apart from gallstones, they are uncommon, particularly after keyhole surgery. Ask your surgeon to talk them through with you. They’ll give you more information about how likely they are for you.

• British Obesity and Metabolic Surgery Society

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