Why do you have to starve for more than 24 hrs before your surgery?

All I have heard is that you are not allowed to eat OR DRINK (EVEN WATER) after 12am the day before your surgery… which will be more than 24hrs by the time you are actually in surgery! Am I hearing/reading this right? If so, what is the logic behind that! So we go in starved and dehydrated? I am rather thin w/ a fast metabolism so I can see this not being good for me (like on the verge of fainting bad) and wouldn't u want to go into surgery healthy? Please explain??

Doctor Answers 16

No Eating/Drinking Before Surgery.

You have to have nothing by mouth for 8 hours before surgery.  This is for safety reasons.  This prevents stomach contents from entering the lungs when having anesthesia.  8 hours of nothing by mouth will be totally worth your safety and beautiful results.  Good luck.


Austin Plastic Surgeon
5.0 out of 5 stars 78 reviews

Why nothing by mouth before surgery

Fasting before surgery is a long established tradition for anesthesia providers although the exact terms vary according to conditions and doctor. Most institutions require nothing after midnight the night before; I think you are almost certainly misinterpreting this as noon the day before.

The reasoning behind this is quite simple. When you are "put under", the muscle keeping what  is in your stomach down there relaxes, and stomach contents including stomach acid can come up, go into your airway, and down into your lungs. This is potentially catastrophic, causing all sorts of breathing issues or even death. Unless surgery is an acute emergency, we want to avoid this as even a remote possibility.

Usually five or six hours is enough time for the stomach to clear, but to be safe, and because schedules sometimes change, even patients having their surgery at noon or later are often "NPO" after midnight the night before.

Benjamin Gelfant, MD
Vancouver Plastic Surgeon
4.9 out of 5 stars 61 reviews

Nothing by Mouth before Surgery

Because your gag reflex is relaxed when you are under deep sedation or general anesthesia, there is a risk of the stomach contents coming up and emptying down the trachea and into the lungs. This can cause a very serious (and sometimes lethal) condition known as aspiration pneumonia.

By not eating or drinking after midnight, you will have an empty stomach by the time you go to surgery, greatly diminishing the risk of aspiration pneumonia. Since your surgery is the next day, you shouldn't need to starve from more than 24 hours.

Traditionally patients have been asked to take nothing by mouth for eight hours before surgery, but, according to the link from the Department of Anesthesia at the University of Michigan, (quoted from the link below):

"The current recommendations by the American Society of Anesthesiologists for NPO status (ie., the number of hours a patient must fast—no food or water—before being taken to the operating room):
AdultsThe recommendations below apply to healthy patients who are undergoing elective procedures. They are not intended for women in labor. If you have special needs (diabetes, among others) consult with the preoperative clinic to see what options may be available.
  • 8 hours for a normal meal
  • 6 hours for a light meal (toast and clear liquids)
  • 2 hours for clear liquids
Children and infants
  • 6 hours for solids and infant formula
  • 4 hours for breast milk
  • 2 hours for clear liquids
Examples of clear liquids include water, fruit juices without pulp, carbonated beverages, clear tea, and black coffee."

The rules may leave you hungry and thirsty, but they are for your own safety.

Heather J. Furnas, MD
Santa Rosa Plastic Surgeon
4.9 out of 5 stars 29 reviews

Fasting Required before General Anesthesia

Usually clear liquids like water are permitted up to 6 hours prior to surgery and full liquids 8 hrs and solid foods 12 hours prior to surgery to prevent aspiration (vomitus goes down windpipe to lungs). This period is determined by the anesthesiologist and an important safety step which could save your life in some cases.

Why do you have to starve for more than 24 hrs before your surgery?

The recommended time to avoid eating or drinking before surgery is 8 hours.24 hours.  The importance of this is that there must not be food in the stomach when you're intubated for anesthesia.  The risk would be that if you have stomach contents and choke or gag during anesthesia induction fluid could be aspirated into your lungs.  Discussed your surgery time in detail with your plastic surgeon to follow the 8 hour rule.

Nothing by mouth before surgery

The stipulated time is 8 hours before your surgery, after this you can not eat or drink nothing. This is like this because you need an empty stomach before surgery and in this way reduce the risk of food going to the lungs. Good luck

Tania Medina de Garcia, MD
Dominican Republic Plastic Surgeon
4.6 out of 5 stars 362 reviews

No eating or drinking after midnight before surgery

Nothing by mouth (NPO) after midnight is common practice to prevent stomach contents from entering lungs.  The "midnight" rule is because surgeries are typically done in the morning and that would allow 8 hours for the stomach to be empty.

If your surgery is later in the day, ask your surgeon and anesthesiologist.  They may have a different recommendation for you.

NPO (nothing by mouth) before surgery.

It is important to not eat or drink for 8 hrs before surgery. No need to fast for 24 hrs. The reasoning behind this is to reduce the risk of aspirating (food entering into the lungs) which can be a serious issue. Small sips of water are acceptable to take medications.

Michael E. Ciaravino, MD
Houston Plastic Surgeon
4.8 out of 5 stars 115 reviews

Fasting Prior to surgery

At our hospital, it is a standard to wait 8 hours prior to surgery. I do know that sips of water are acceptable even within the 8 hour fasting period for the purposes taking medications.

Arian Mowlavi, MD
Orange County Plastic Surgeon
4.9 out of 5 stars 45 reviews

Why do you have to starve for more than 24 hrs before your surgery?

Just some miscommunication; nothing to eat or drink after 12 PM ( 8 hours before surgery).  An empty stomach   at the time of surgery will help prevent food “going the wrong way” to the lungs.  Best wishes.

These answers are for educational purposes and should not be relied upon as a substitute for medical advice you may receive from your physician. If you have a medical emergency, please call 911. These answers do not constitute or initiate a patient/doctor relationship.