Starvation Before Surgery: How Fasting-From-Midnight Can Slow Your Recovery

starvation before surgery clearfast

At ClearFast, we’re all about empowering patients with the knowledge they need to have the best surgery experience possible—and, if you’ve been following along on our blog, you probably know that a big part of a successful surgery experience lies in avoiding starvation before surgery. Today, then, we’re diving into what happens to the body when you deprive it of food before your procedure. 

We’ll cover:

  • Where your body gets its energy when you don’t eat for an extended period of time
  • How muscle breakdown can occur as a result of starvation before surgery
  • The affect starvation before surgery has on your body’s ability to recover

Now, let’s dig in…

What happens to the body when you don’t eat for an extended period of time? 

When you’re nourishing yourself regularly, your body breaks down glycogen, turning it into glucose which it uses for energy. According to Science Alert, about 25% of that energy goes to feeding your brain, while the other 75% powers your muscle tissue and red blood cells. After about six hours of fasting, however, you begin to run out of glycogen stores—and your body has to make a critical shift and begin getting its fuel elsewhere, including from muscle tissue. This eventually leads to muscle breakdown.

Can your body enter starvation mode as a result of fasting before surgery? 

Unless you’re lucky enough to snag the first surgery slot of the day, fasting-from-midnight can often mean you’re stuck waiting for surgery for up to 17 hours with no sustenance—meaning “fasting before surgery” can quickly turn into starvation before surgery. In fact, according to an article published in British Journal of Anaesthesia, a study of 190 patients found that 70% of patients had to fast over twice the recommended length of time for both food and drink—and that 97% were starved longer than required.

While we always recommend you listen to your doctor’s specific instructions regarding fasting before surgery, it’s important to note that fasting-from-midnight is a non-evidence-based practice. It’s now often being replaced with instructions to nourish and hydrate with a clear, complex-carb-rich presurgery drink up to two hours before your procedure. Consuming proper nourishment in the form of a presurgery carbohydrate drink like ClearFast allows your body to nourish itself (so it doesn’t have to start breaking down muscle tissue for that all-important energy)—and provides a ton of other benefits for a seamless surgery experience as well (including a drastically reduced risk of post-op nausea and vomiting, easier IV “sticks”, a reduced risk of surgical infection, and reduced stress before surgery). In fact, you can read more about the benefits of replacing your fast with a presurgery drink here.  

What role does starvation before surgery play in my ability to recover? 

We say this all of the time (because it’s true!): undergoing surgery is like a running marathon. It’s an event that puts a ton of physical and mental stress on your body, and the better prepared you are when you begin it, the better your end result will be. You’d never enter into a marathon starved and dehydrated, and the same goes for surgery—when you think about it, it doesn’t make much sense to go under the knife lacking proper nourishment and strength. When you send yourself into a point of starvation before surgery, your body begins to run low on glycogen and eventually breakdown your muscle tissue to get energy; as a result, you run an increased risk of extended recovery time and—the thing absolutely no one wants—a longer hospital stay. 


Overall, starvation before surgery plays a major role in your body’s ability to properly—and quickly—recover. If you have a procedure coming up, talk to your doctor about ClearFast’ing in place of fasting—and order your ClearFast Presurgery Drink here when you’re ready. And, as always, reach out to our team at support@drinkcf.com if you have any questions at all. We’re always here and happy to help make your surgery experience a successful one!

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