Foods to Avoid Before Colonoscopy: List of Foods Banned on the Low-Residue Diet and Clear Liquid Diet

Foods to Avoid Before Colonoscopy: List of Foods Banned on the Low-Residue Diet and Clear Liquid Diet
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For years, people have complained to their doctors that the “prep,” or leadup to their colonoscopy, is many times worse than the procedure itself. While in the past colonoscopy prep has been heavily weighted towards a clear liquid diet for several days prior to the procedure, many doctors have relaxed this stringent regimen and now allow their patients to follow what’s known as a low-residue diet up to the day before their colonoscopy.

Preparing for Colonoscopy: The Low Residue Diet

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One of the main goals of colonoscopy prep is to empty and cleanse the entire colon. This is very important, because if the bowels are not clean, the doctor performing the procedure may not be able to see the walls of the colon clearly, and possibly miss signs of polyps or other conditions.

A low-residue diet is designed to assist you in cleansing your colon prior to colonoscopy. It’s made up of easy-to-digest, low-fiber foods that pass easily through the entire digestive tract, especially the bowels. Along with laxatives, a low-residue diet followed by a clear liquid diet a day or so beforehand will optimize the success of the procedure. Remember to always follow your physician’s recommendations and use this article only as a supplementary guide.

Foods to Avoid Before a Colonoscopy

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On a low-residue diet, high fiber and tough-to-digest foods are verboten. Whole grains, raw vegetables and fruit, dried fruit, nuts, seeds, berries, corn and popcorn must all be avoided. While these foods normally comprise a healthy diet and actually help to protect against colon problems like diverticulosis, the very qualities that make them healthful also make them incompatible with colonoscopy cameras.

Usually your physician will recommend avoiding the following foods for up to several days prior to your colonoscopy.


  • Whole grain breads, crackers, and cereals
  • Corn in any form, including popcorn
  • Brown or wild rice
  • Granola
  • Buckwheat
  • All whole grains


  • Raw vegetables, especially cruciferous vegetables, and including beans, broccoli, Brussels sprouts, cabbage, cauliflower, kale, onions, peas, squash, and Swiss chard


  • Raw or dried fruit
  • Berries
  • Prune juice

Nuts and Seeds

  • Avoid all nuts and seeds


  • Tough or fibrous meats

The Clear Liquid Diet

For a day or so prior to the colonoscopy, physicians usually recommend an even more stringent regimen: the clear liquid diet. When it comes to this stage of colonoscopy prep, nearly all foods are off the list.

On a clear liquid diet you may consume only liquids such as broth, water, plain tea, black coffee, clear juices, and Jell-O. Red, blue, or purple colored liquids aren’t allowed on the clear liquid diet.

When following this list of foods to avoid before colonoscopy, keep in mind that the purpose is to cleanse the colon and the method is to avoid high fiber, slow-to-digest foods. Your physician will most likely provide you with their own list of foods to eat and foods to avoid. It will be very much like this one, but be sure to follow their recommendations. Preparing for colonoscopy with a low-residue diet and clear liquid diet is the best way to ensure a successful colonoscopy procedure.


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