Clear Liquid Before Surgery: The Meaning Behind the ClearFast Name & Why It Matters for Safer Surgery

What’s in a name? Turns out, a whole lot, actually. With a name like ClearFast, we often get asked if our drink is a laxative (spoiler alert: it’s not!), so we wanted to take some time today to explain the meaning behind our product’s name and—more importantly—to cover what in the world its name has to do with safer surgery. Today, we’ll cover:

  • What the name “ClearFast” means
  • Why a pre-surgery drink needs to be formulated to clear from your stomach in a timely manner
  • Why drinking clear liquid before surgery ultimately makes for safer surgeries
  • How ClearFast is designed to clear from your stomach fast and reduce your risk of a dangerous surgery

Now, let’s dig in…

What does the name ClearFast mean?

The name ClearFast comes from the idea that our pre-surgery drink is formulated to clear from your stomach, fast. (Another handy way to look at it is this: it’s a clear liquid for your pre-surgery fast). The name actually has nothing to do with the product being a laxative at all! Why, though, does it matter if something clears from your stomach fast? We break that down below, so read on!

Why does my pre-surgery drink need to clear from my stomach fast?

One of the main reasons patients are instructed to not eat or drink anything after midnight before their surgery is because matter left behind in the stomach can put a patient at risk of aspiration during surgery. Aspiration is essentially the entry of your stomach contents into the lower respiratory tract and lungs, which can be very dangerous when you’re under anesthesia. Modern medical research has concluded, though, that patients who drank clear liquid before surgery had even emptier stomachs than patients who didn’t eat or drink anything before their surgery, ultimately reducing their risk of aspiration.

How does drinking clear liquid before surgery leave you with an emptier stomach than if you didn’t drink anything at all?

So how, exactly, does drinking clear liquid before surgery leave patients with an emptier stomach than not eating or drinking anything at all? It does sound a bit counterintuitive, after all! Turns out, when we fast from midnight (the outdated rule), an empty, hungry stomach can cause a buildup of gastric acids. Recent studies have shown that patients entering surgery after using a clear liquid like ClearFast have lower acidity of stomach contents than those who fasted and, therefore, a reduced risk of aspiration under anesthesia. In short, drinking clear liquid before surgery is proven to leave you with an emptier stomach, which makes for safer surgery.  

So what makes ClearFast clear from my stomach fast?

In order to ensure safer surgery and reduced risk of aspiration, the pre-surgery drink you choose needs to be specially formulated to clear from your stomach fast. This has to do with something called osmolarity. Osmolarity is essentially the concentration of a substance (in this case, complex carbohydrates) in a solution (the drink itself). Lower osmolarity leads to faster gastric emptying times…which ultimately leads to a reduced risk of aspiration and safer overall surgery.

ClearFast has an ideal osmolarity of 270 mOsm, which makes for timely gastric emptying. (Sports drinks, on the other hand, have a high osmolarity of around 330 mOsm, which means they stay in your stomach way too long to be considered safe to use as a pre-surgery drink.) Overall, ClearFast was specially formulated to address physicians’ concerns (the concern of patients entering into surgery with left-behind stomach contents) and make for safer, easier surgeries for patients by allowing them to nourish and hydrate before surgery rather than starve themselves after midnight. (Psst…you can also read more about everything ClearFast does to make for more comfortable surgeries—including reducing your risk of post-op nausea and vomiting—here.)


Overall, drinking the right clear liquid before surgery is such a simple and easy way to get a leg up on the dreaded surgery and recovery process. Ready to give ClearFast a try? Order your ClearFast Preop Drink here, or reach out to the ClearFast team at if you have any questions about the process at all.