It’s not news that colonoscopy is a wonderful screening and diagnostic tool. What you may not know: According to the American College of Gastroenterology, bowel preparation is inadequate in up to 20% to 25% of colonoscopies. This means you may get inaccurate results, including missed abnormalities, or you may be asked to reschedule the test involving another round of the dreaded prep! 

In the typical colonoscopy prep, patients need to drink a laxative solution anywhere from 12 to 24 hours before the procedure in order to empty the bowels completely­. Unfortunately, many patients do not accomplish this goal—sometimes they don’t finish the solution due to a strong reaction such as nausea, vomiting and/or painful elimination, they start the prep too late or they don’t follow other instructions.   

I’ve developed a plan for my patients that makes typical colonoscopy prep more successful and gentler on the system. The object is to gradually reduce stool volume for a few days before you even begin drinking the prep solution. This helps ensure that the bowels will be well prepared for the test. What I suggest…

Four days before your colonoscopy, make your diet simple and clean. Your goal is to have one or two good-sized, complete stools each day during the days prior to drinking the colonoscopy prep solution. To help achieve this… 

  • Avoid fried and high-fat foods. Use olive oil and mashed avocado for fats.
  • Become a vegetarian or limit protein to fish or a small amount of turkey. Eat lots of baked or steamed vegetables. Avoid salads and limit raw vegetables to one or two small servings per day. 
  • Avoid corn, nuts, berries and legumes as they can sometimes linger in the bowel. Whole grains, such as brown rice, are OK.   
  • Limit fruit to apples and pears. Applesauce and baked apples and pears are excellent—delicious and high in fiber.  
  • Avoid dairy because it’s often not easy to digest. 

Also, cut out any foods with dyes as well as beets, which can discolor your bowel wall. And avoid preservatives and sugar substitutes and alcohols, which can irritate your colon. These ingredients may affect your test results. 

Thirty-six hours before your colonoscopy, switch to an all-liquid, low-protein, low-fiber diet. Drink only clear or lightly colored fruit juices, such as apple or pear…miso…broth…preservative- and color-free, unsweetened electrolyte solutions…and lots of water. Black coffee or tea is OK. Do not drink milk or nondairy milk (soy, almond, etc.). 

After using my plan, begin your colonoscopy prep as directed by your doctor. Hydrate with water up until the time your doctor has told you to stop drinking.

After a colonoscopy. Load up on probiotics. I advise an acidophilus/bifidus supplement, 20 billion colony-forming units (CFUs), for 14 days. Caution: If you have a severe illness or a significantly compromised immune system, talk to your doctor before using probiotics—they can increase risk for infection in these individuals. For three days after, rehydrate with lots of water and eat a simple diet of whole foods.