Frequently asked questions about fasting guidelines for adults

What can I eat and drink the night before and day of my procedure/surgery?

8 hours before your procedure

Unless told differently by your doctor, do not eat food for 8 hours before your procedure (even food or formula given through a feeding tube).

6 hours before your procedure

Do not drink non-clear fluids, such as milk, hot chocolate, or coffee or tea with milk, cream, or nondairy creamer, for 6 hours before your procedure.

Up to 2 hours before your procedure

  • You may drink clear fluids until 2 hours before your procedure if your doctor approves. Clear fluids are:
    • Apple or white grape juice (not orange juice)
    • Black coffee
    • Clear tea
    • Carbonated drinks, such as cola, ginger ale, Sprite®
    • Sports drinks, such as Gatorade®
    • Water
  • Remember:
    • Clear fluids cannot be hazy or cloudy. They cannot have pulp or fats.
    • No milk, creamer, or lemon added to any drinks.
    • No alcohol.
    • Do not swallow gum, mints, or candy.

Your stomach must be empty for your procedure. We do not want food from your stomach to get into your lungs. Your procedure will be delayed if you do not or cannot follow these instructions.

Why can’t I eat or drink before my procedure?

Our protective reflexes slow down when we are given anesthesia. One protective reflex is to keep food and liquids in the stomach from going into our airway. Aspiration can happen when food or liquids from our stomach get in our airway. This is less likely to happen when your stomach is empty. Fasting (not eating or drinking) keeps your stomach empty.

Why is aspiration bad?

Solid or semi-solid food in the stomach may not let your lungs get air. Liquid from the stomach that is acidic may burn your lungs and stop you from getting air. Both can cause brain damage or death.

Aspiration can be treated. Most people survive, but treatment in an intensive care unit (ICU) is often needed. It may keep you in the hospital days to weeks longer.

Can I chew gum or suck on hard candy while waiting for my procedure?

Adults (18 years and older) can chew gum or suck hard candy. A procedure should not be cancelled or delayed because a person is chewing gum or sucking hard candy. Do not swallow gum or hard candy. This will count as a meal, and you will need to wait 8 hours your procedure.

When should I stop chewing tobacco or putting snuff in my mouth before my procedure?

Stop 6 hours before your procedure.

I was in a car accident and need emergency surgery. It has only been 4 hours since I ate. My doctor says I need the surgery now. Why do I not have to wait 8 hours?

Guidelines help doctors and patients decide about health care. Fasting guidelines are not meant to be the final decision. The risk of aspiration must be weighed against the risk of not having surgery quickly. Your anesthesiologist may change the type of anesthesia to lower your risk.

If I take food through an enteral or nasogastric tube (gastric/stomach tube, enteral/jejunostomy tube), should I follow the same instructions?

Stopping feeds for 8 hours is preferred. People who have residual volumes checked, can stop feeds 4 hours before the procedure if these volumes are not going up. Feedings should stop at the first sign of higher stomach residual volumes.

Continuous duodenal feedings have less risk of aspiration than stomach feedings. The urgency of the surgery and need for continuous nutritional support versus the higher risk of aspiration needs to be considered by the patient and all health care providers involved in the care.

Why can I use apple jelly to take crushed medicines?

Apple jelly is made from apple juice that has been boiled and cooled. This causes it to thicken. Apple juice is an approved clear fluid.

Plain apple jelly can be used to take crushed pills up to 2 hours before a procedure. Do not use pudding or apple sauce.

Who came up with the fasting guidelines?

They are based on research and expert opinion. The American Society of Anesthesiologists and the European Society of Anesthesiologists each have a task force to make them. Doctors in the Department of Anesthesia at the University of Iowa Health Care adapt these guidelines.

Last reviewed: 
September 2020

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