If you are overweight, the best way to lose weight is by making long-lasting changes to your diet and level of physical activity. You can learn how by reading more articles in Lose weight.
But in cases where lifestyle changes, accompanied by weight loss medicines when appropriate, are not enough, then weight loss surgery, also called bariatric surgery, may be an option.
When considering weight loss surgery, it’s important to bear the following in mind:
- Weight loss surgery should be seen as a last resort.
- Not everyone is eligible to have it done on the NHS.
- After surgery, you will never be able to eat the same way again, or you will become very ill if you do.
- After surgery, you will need to follow a carefully controlled diet and take regular exercise.
You’ll need to show that you’ve changed your diet and lifestyle before the operation, and you'll have to stick to long-term changes afterwards. But surgery can help very overweight people to lose significant excess weight.
If you’re interested in weight loss surgery, talk to your GP to learn more.
What is weight loss surgery?
There are two main kinds of weight loss surgery.
- Gastric banding. Here, a band is fitted around the top of the stomach. This causes a feeling of fullness after eating a very small amount of food, and means that food must be eaten very slowly.
- Gastric bypass. Here, a much smaller stomach is made. This causes a feeling of fullness after eating a small amount of food, and means that the body absorbs fewer calories.
Both procedures are designed to be permanent. Learn more about these and less common weight loss operations.
Who can have weight loss surgery?
Your GP can assess you to see if weight loss surgery is right for you.
To be considered for weight loss surgery on the NHS, you should have a body mass index (BMI) of:
- 40 or more
- (or) a BMI of between 35 and 40 along with a weight-related health condition, such as type 2 diabetes or high blood pressure
You can find out your BMI by using our Healthy weight calculator.
You should also:
- be able to commit to long-term follow-up appointments after the operation
- have tried to lose weight by changing your diet and exercise levels for at least six months
- be healthy enough to have an operation under general anaesthetic
Even if you pay for private surgery, it's still likely that your surgeon will only agree to the operation if similar criteria are met, because of the risks associated with such major surgery.
What does the operation involve?
Before the operation
If your GP thinks that weight loss surgery is right for you, you’ll be referred to a specialist weight loss team.
A consultant will assess you to decide if weight loss surgery is the right step to take. The consultant should explain more to you about the different types of surgery. They should also discuss the weight loss that can result, and the changes to your lifestyle that you will need to make afterwards.
They will also discuss the risks and possible side effects of surgery. Weight loss surgery is carried out under general anaesthetic. Serious complications with general anaesthetics are rare, but can be more likely when you are overweight.
If you and the specialist team decide to go ahead with surgery, you should be offered ongoing psychological support and help with changing your diet and lifestyle before the operation.
Many people who undergo weight loss surgery must go on a special, very low calorie diet before having the surgery. This is meant to lose the excess fat stored in the liver, so that surgeons are able to carry out the operation. It's important for you to meet a dietitian who can help you with this diet, and it is essential that you stick to it.
Having the operation
The type of weight loss surgery you have will depend on your circumstances, including how overweight you are and any other health problems you have.
Most people who have a gastric band operation stay overnight in hospital, but this varies between treatment centres.
With a gastric bypass, the stay in hospital is typically between one and three nights.
After the operation
Your specialist team should schedule several follow-up appointments running across a year or more, and it is important that you attend all of them.
This ongoing specialist team support is vital to the long-term success of the surgery, because it will help you to change former eating habits, and to adapt to a new lifestyle.
Remember, after your operation you will never again be able to eat as you did before. This means changing your eating patterns. A dietitian in your specialist team will be able to help you with this.
They will give advice on a healthy diet and supplements that will provide you with the nutrients and energy you need.
If you were fitted with a gastric band, it may be necessary to adjust it. This is done by injecting fluid into a small port that sits underneath the surface of your skin, and if necessary it will be done at follow-up appointments.
Following weight loss surgery, you will feel full after very small portions of food. You’ll need to eat small portions of food at mealtimes. It will take much longer to eat, and you’ll have to chew food very thoroughly. If you try to eat too much you may experience discomfort, or may vomit.
How long after surgery would I start losing weight?
Your weight loss will also be monitored at the follow-up appointments. If you have been fitted with a gastric band, you should aim for a steady rate of weight loss at around 1lb or 2lb (about 0.5kg or 1kg) a week, that continues for a year to 18 months.
If you have had a stomach bypass it is common to lose weight faster than this at first. But over time, the weight loss resulting from gastric bypass and gastric band procedures is the same.
If you were very overweight, you may not achieve a healthy BMI even once your weight loss has stopped. But moving closer to a healthy BMI will decrease your risk of serious health conditions, such as type 2 diabetes, heart disease, stroke and cancer.
Once you have recovered from surgery, exercising regularly will help you to achieve and maintain a healthy weight.
You can find more information and advice in recommendations after weight loss surgery