Nutrition

Eating well before surgery

Good nutrition in the weeks before your operation helps your body prepare for the physical stress of surgery and supports faster healing afterwards.

Eat regular meals with a good source of protein at each one (meat, fish, eggs, dairy, legumes, or tofu).
Eat plenty of vegetables and fruit to provide vitamins and minerals that support healing.
Stay well hydrated. Aim for 6–8 glasses of water per day. Limit sugary drinks and excessive caffeine.
Try to maintain a healthy weight. If you are significantly underweight or have lost weight recently, tell your surgical team. You may benefit from nutritional support before your operation.

Fasting before surgery reduces the risk of complications during anaesthesia. When you are under general anaesthesia or sedation, your body's natural reflexes, such as coughing, are switched off. If there is food in your stomach, it can travel up into your throat and into your lungs. This can be life-threatening, so it's important to follow your team's instructions.

6 hours before surgery

Stop eating solid food. You may continue to drink clear fluids. No milk, smoothies, or fizzy drinks. Adults aged 16 years and older can drink up to 200 mL (about half a cup) per hour of clear liquids up until the time you are taken into the operating theatre. You can chew gum but make sure to spit it out before going into theatre.

If you have diabetes, reflux, or take GLP-1 weight-loss medications or peptides, you must discuss this with your doctor in advance, as the fasting rules may be slightly different for you. The rules are also different for babies, infants, and children under the age of 16.

Protein is the building block your body uses to heal wounds, rebuild muscle, and fight infection. In the weeks before surgery, aim to eat more protein than usual.

Target: 1.2–1.5 grams of protein per kilogram of body weight per day. (For a 70kg person, that is 85–105g per day.)
Good food sources: chicken, fish, eggs, Greek yoghurt, cottage cheese, lentils, chickpeas, tofu, and nuts.
Protein supplement drinks (e.g., Fortisip, Ensure, Complan) can be helpful if your appetite is poor or you are struggling to eat enough. These are available from pharmacies without a prescription.

If your surgical team recommends specific nutritional supplements, take these as directed. Tell your team if you are finding it difficult to eat enough. Nutritional support services are available.

Alcohol

Stop drinking alcohol at least 4 weeks before surgery. Alcohol increases bleeding risk, impairs wound healing, suppresses immune function, and affects how your body responds to anaesthesia and pain relief.

Smoking

Stop smoking as early as possible, ideally 8 weeks before surgery. Smoking significantly increases the risk of wound infection, chest complications, blood clots, and slower healing. Your GP can help with cessation support.

Herbal supplements

Stop all herbal and natural supplements at least 2 weeks before surgery. Many affect bleeding or interfere with anaesthetic drugs. This includes: garlic capsules, ginkgo biloba, ginseng, St John's Wort, kava, valerian, and high-dose fish oil.

Grapefruit

Avoid grapefruit and grapefruit juice in the week before surgery. Compounds in grapefruit block a liver enzyme that breaks down many medications, including some used in anaesthesia and pain management.

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