Preparing for Weight loss Surgery

Your pre-surgery diet and activity.

Your dietitian may give you a special diet to follow during the weeks leading up to your surgery. The diet will help to shrink your liver so it’s easier for the surgeon to access your stomach.

Losing weight before surgery is often recommended as it can reduce the risks associated with general anaesthesia. It can also reduce the risk of complications afterwards.

Your surgeon may also recommend that you increase your level of physical activity.



Your surgeon may ask you to have a psychological assessment to check if you have any emotional problems that could make it difficult for you to cope with the lifestyle changes you need to make after surgery. Your psychologist can help you learn to manage emotional stress and other factors that trigger you to eat. They can also help you make behavioural changes that can lead to a healthier lifestyle.


You may need to have a nutritional assessment with a specialist dietitian to make sure you understand the changes you need to make to your diet. A good dietitian will also give you advice about food preparation and reading food labels to help you keep track of your caloric intake.


If you have signs of cardiovascular disease, your anaesthetist may ask you to see a cardiologist to make sure your heart is healthy enough for the surgery and anaesthesia.


If you’re taking medication for diabetes, your surgeon may ask you to reduce the dose. They’ll also let you know if there are any other medications you should take, or avoid.

Tests and imaging

Before surgery you may need to have some tests and imaging, including:

  • blood tests
  • chest X-ray
  • electrocardiogram (ECG)
  • sleep study for obstructive sleep apnoea.

Your doctor may ask you to have a gastroscopy, a test that lets your doctor look inside your oesophagus (the pipe that leads to your stomach), stomach, and duodenum (top part of your small intestine). This is to check for abnormalities that might affect your surgery.

If any issues are raised by your tests and imaging, your surgeon may have to postpone or cancel your surgery.


If you smoke, your surgeon may insist you stop before surgery. Although weight loss surgery is relatively safe, the risk of death is double in people who smoke. Smokers also have a 30% complication rate after surgery, which is 1½ times the rate for non-smokers. Smoking increases the risks of blood clots, pneumonia, ulcers and wound infection. Smoking is a contraindication for some forms of bypass surgery. 

Many smokers with weight problems think it helps them control their weight. If you're one of them, the positive effects of weight loss surgery and lifestyle changes are yet another incentive to quit.

Learn more about quitting


The type of anaesthetic and post-op pain relief you may be offered.


Information is provided by HCF in good faith for the convenience of members. It is not an endorsement or recommendation of any form of treatment nor is it a substitute for medical advice, and you should rely on the advice of your treating doctors in relation to all matters concerning your health. Every effort has been taken to ensure the accuracy of the information, however HCF takes no responsibility for any injury, loss, damage or other consequences of the use of this information.