The Definition of a Clear Liquid Diet for Colonoscopy

Black coffee is one of the clear liquids allowed before your colonoscopy.
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It's important to prepare for your colonoscopy the right way so your doctor has a clear view of your colon when they perform the exam. Part of that prep includes following a clear liquid diet before your colonoscopy by sticking to foods like broth, sports drinks and ice pops.

Tip

Following a clear liquid diet before a colonoscopy means you should only have foods that are free of solids and pulp and that you can see through, like clear broth.

What's a Clear Liquid Diet?

Consuming a clear liquid diet — along with prescribed laxatives — for the day or two before your colonoscopy helps clean out your intestines so your doctor has an unobstructed view of your colon, according to Harvard Health Publishing. This diet also provides some energy, electrolytes and hydration to compensate for the laxatives, per the Mayo Clinic.

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So what's a clear liquid? It's any food or beverage that is transparent, instead of cloudy or opaque. These liquids should not contain solids, like pulp in juices. Clear broths for colonoscopies should likewise be solid-free: for instance, soups without noodles or vegetables.

You'll typically also stick to a low-fiber diet free of whole grains, nuts and raw produce in the few days before your colonoscopy to get a head start with emptying out your GI tract, according to the Colorectal Cancer Alliance.

Tip

How do you tell if your liquid is clear enough? It should be see-through at room temperature, according to MedlinePlus.

Clear Liquids to Try

While a clear liquid diet limits what you can eat before a colonoscopy, you don't just have to stick to water and clear broth. Here are some other colonoscopy-friendly liquids and snacks, according to Harvard Health Publishing:

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  • Pulp-free juice like white grape or apple juice
  • Electrolyte sports drinks
  • Clear sodas like ginger ale
  • Tea or coffee (without milk or cream)
  • Ice pops or fruit ice
  • Clear hard candy like lemon drops
  • Fruit-flavored gelatin or Jell-O
  • Clear soups and broths like vegetable, beef and chicken broth or bouillon
  • Clear nutrition or protein drinks like Ensure Clear, per UVA Health

Warning

It's important to note that the clear liquid diet for colonoscopies is meant for short-term use only. While it provides some carbs for fuel, it's very low in protein, essential fats, vitamins and minerals, so you shouldn't stay on it for more than a few days unless your doctor recommends it, according to the Mayo Clinic. And this type of diet should never be used for weight loss.

Liquids to Avoid

You should avoid milk before a colonoscopy because it could leave a residue on your intestines, making it harder for your doctor to get a good view.
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There's a reason your colonoscopy prep specifically requires that you follow a liquid diet.

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Consuming solid foods or cloudy liquids can leave residue in your colon, according to Harvard Health Publishing. And that residue can prevent your doctor from getting a good view of your intestines, which could conceal small polyps or mean you have to repeat the procedure entirely.

1. Liquids That Aren't Clear

Per the Colorectal Cancer Alliance, common foods and liquids to avoid include:

  • Milk and other dairy products
  • Coffee or tea with milk added
  • Juice with pulp, like orange or prune juice
  • Ice pops made with chunks of real fruit
  • Soups with vegetables, noodles, rice or cream
  • Anything pureed that is cloudy or creamy
  • Stock, miso soup and bone broth: Though they may appear to be clear liquids, these products often contain small particles of vegetables or fat that make them cloudy, so you might want to play it safe and avoid them before your colonoscopy.

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2. Red, Blue and Purple Liquids

Some doctors also recommend avoiding red, blue and purple foods or beverages, according to the Colorectal Cancer Alliance. Why? The coloring can stain your colon and make it harder to view the surface of your intestines, which could potentially mess with your results, per Moffitt Cancer Center.

Follow your doctor's instructions when it comes to colorful food. Some potential snacks to avoid in red, blue and purple flavors include:

  • Grape juice
  • Flavored gelatin or Jell-O
  • Sports drinks
  • Ice pops
  • Hard candies

Tip

When in doubt, ask your clinician for an approved list of foods and drinks that are safe to eat before your procedure.

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Is This an Emergency?

If you are experiencing serious medical symptoms, please see the National Library of Medicine’s list of signs you need emergency medical attention or call 911. If you think you may have COVID-19, use the CDC’s Coronavirus Self-Checker.
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