What Happens If... You Eat Or Drink Before An Operation?

How risky is it not to fast before going under anaesthetic?
Karen Moskowitz via Getty Images

Not every operation means you can’t eat or drink beforehand – but for most major ops, you’ll probably have to steer clear of the buffet before going under anaesthetic.

Whether you’re allowed to scoff or not all depends on what kind of anaesthetic you’re having and what kind of operation you’re facing.

But don’t worry, the healthcare professionals in charge of organising your operation will tell you:

  • if you can eat or drink beforehand
  • what foods and and liquids you can have, if any
  • if eating and drinking are allowed, how soon before the operation you might need to stop.

According to the NHS, local anaesthetic will let you eat and drink as normal before your procedure (although there might be special rules if the operation involves your digestive system or bladder).

But, if you have a general anaesthetic, you’ll almost definitely not be allowed to eat or drink before the operation.

That’s because it will make you unconscious, meaning you can’t feel anything and your body’s natural reflexes will be stopped.

The NHS website explains: “If you stomach has food and drink in it, there’s a risk of vomiting or bringing up food into your throat.

“If this happens, the food could get into your lungs and affect your breathing, as well as causing damage to your lungs.”

That’s because your body won’t be able to cough it back up, according to Very Well Health.

Having undigested food in your body can also increase the risk of interference for bowel prep or infection and add more surgery complications.

As the NHS website continued: “The amount of time you have to go without food or drink (fast) before you have your operation will depend on the type of operation you’re having.

“However, it is usually at least 6 hours for food, and 2 hours for fluids.

“You’ll be told how long you must not eat or drink for before your operation.”

It’s not just food and drink either. You should try not to chew any kind of gum, including nicotine gum, during this period as well.

Tragically, tea and coffee with milk are also on the no-go list. That’s because if you vomit after having the drinks, it could get into lungs and damage them – so try to just stick to water.

For infants, they can have breast milk up until four hours before an operation but after that, they should only have clear fluid.

Those with conditions like diabetes (where fasting is not really an option) will need specific advice from their healthcare professionals.

If you do eat or drink anything other than water, your operation might well be postponed.

And, though you might fancy having a huge meal before you start your fast, it’s best to have a light meal which takes less time to digest.

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