The Definition of a Clear Liquid Diet for Colonoscopy

Black coffee is one of the clear liquids permitted in colonoscopy preparation.
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Before you have a colonoscopy, it's important that you prep 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 at least one day before your procedure that includes only clear broth and other clear liquids.


When you follow a clear liquid diet to prep for a colonoscopy, it’s important to eat or drink only liquids or foods that are free of solids and pulp and that you can see through, like clear broth.

What Are Clear Liquids?

Clear liquids include any foods or beverages that are clear or transparent, instead of cloudy or opaque. They should be free from any solids like the noodles or vegetables found in soups or the pulp that's found in juices.

MedlinePlus states that the foods should be clear and see-through when at room temperature. Following this diet for a day or two, or as directed before your colonoscopy, will give your GI tract and your large intestine a chance to empty out.

Read more: Why is a High Fiber Diet Prohibited Before a Colonoscopy?

Not Limited to Clear Broth

A few days before your procedure, you can make a list of a few clear liquid diet ideas for a colonoscopy. There are usually no foods or beverages specified as "required," but a clear liquid diet doesn't give you a whole lot of options either.

Some clear liquids to consider might include:

  • Cranberry, grape or apple juice
  • Electrolyte sports drink
  • Clear sodas like ginger ale
  • Tea or coffee (without milk or cream)
  • Ice pops
  • Fruit-flavored gelatin
  • Any kind of clear broth or soup

According to the Colorectal Cancer Alliance, some doctors recommend avoiding red or blue foods or beverages, so it's best to ask your doctor before planning your menu or purchasing red or blue foods like flavored gelatin or sports drinks.

If you like soup, ask your clinician for an approved list of clear soups that are safe to eat. If they don't have a list, you should be fine with any product labeled as bouillon or broth. Some products labeled as stock or even bone broth may be cloudy or contain small particles of vegetables or fat, so you might want to play it safe and avoid those.

A safe list of clear soups can include chicken or beef bouillon and beef, chicken or vegetable broth.

Liquids That Are Not Clear

It's important to avoid any foods or liquids that aren't clear. These include:

  • Milk
  • Coffee or tea with milk added
  • Juice with pulp, like orange juice 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

According to Harvard Health Publishing, the instructions for your colonoscopy prep are specific for a reason. If you eat any solid foods or drink liquids that are not clear, you run the risk of having bowel residue in your colon.

The biggest problem is that a poor prep can prevent your doctor from getting a good view of your colon and increase the chance that he might miss small polyps. You might also have to repeat your entire procedure, which might be motivation in itself to make sure the clear liquids you drink before your colonoscopy really are clear.

Read more: What Can You Eat When Preparing for a Colonoscopy?

It's important to note that a clear liquid diet 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.