Foods to Avoid & Eat Before a Colonoscopy Procedure

If you have a scheduled appointment for a colonoscopy, your healthcare professional should have informed you about things to do and avoid before the procedure. 

For example, you need to avoid eating specific foods. 

You’re probably wondering why it’s necessary to avoid specific foods, and what you should eat instead. 

Read on to learn more about foods to avoid before the colonoscopy procedure, when to stop eating, and why. 

What is a colonoscopy procedure?

A colonoscopy is an endoscopic exam of the large bowel. The main objective of colonoscopy is to look for swollen, irritated tissues, cancer, polyps, or other changes in the colon and rectum. 

During the procedure, a healthcare professional inserts a colonoscope (a long, flexible tube) into the patient’s rectum. The doctor views the inside of the entire colon thanks to a video camera on the tip of the colonoscope. 

A patient is under sedation or anesthesia during the procedure. Colonoscopy usually lasts between 30 and 60 minutes. 


How do you prepare for a colonoscopy?

The main focus of colonoscopy prep is cleaning out or emptying the colon. To make that happen, the healthcare provider will instruct you to:

Modify your diet 

You’ll need to avoid specific foods before the procedure. We’re going to focus on foods to avoid and eat before a colonoscopy procedure below.

Take a laxative

The doctor may prescribe a laxative in liquid or pill form to help empty the colon. In many cases, the patient needs to take a laxative the night before the procedure. 

Most patients need to take the laxative the night before and the morning of colonoscopy. Liquid laxatives don’t taste good, but you can mix them with something flavored like a powdered drink mix or a sports drink. 

You can also keep the solution well chilled and use a straw to drink it. Just make sure you place the straw far back on your tongue. After drinking the solution, it’s practical to suck on a lemon slice or hard candy.

Adjust medications 

The doctor may adjust the dosages of specific medications or instruct patients to stop taking them temporarily. These medications include those for diabetes, hypertension, and heart problems. 

Patients must inform doctors about medications they’re taking if they’ve changed healthcare providers. This is important to avoid potential side effects.

When preparing for a colonoscopy, it’s also useful to get medicated wipes and skin-soothing products because you are likely to experience high-volume diarrhea. In fact, diarrhea tends to be forceful in this case, which is why you may have bloating or cramps. 

Some patients also develop nausea and start vomiting. If you have hemorrhoids, they may be inflamed. Wear loose clothing and make sure you’re near the bathroom. 

Your stool should look like clear water or urine. That’s when you know the laxatives did their job properly.

Foods to avoid before the colonoscopy procedure 

As mentioned above, colonoscopy prep revolves greatly around diet. Avoiding certain foods is the most important thing you can do to prepare for the colonoscopy procedure. You will receive detailed instructions on what to do or avoid before colonoscopy. The instructions also include diet rules. 

Dietary adjustments start three to five days before the procedure. That’s when you need to ditch high-fiber foods and stick to low-fiber alternatives. 

Foods to avoid before the colonoscopy procedure include the following:


Raw fruit with skin, seeds, and membranes, dried fruit such as raisins, and canned or cooked fruit with seeds and skin.


All vegetables that are raw and come with skin, seeds, and peel. Other vegetables to avoid include corn, onions, lima beans, summer and winter squash, cooked cabbage or Brussels sprouts, potatoes with skin, and tomatoes.

Whole grains and high fiber

Wild or brown rice, whole grain bread, crackers, pasta, high-fiber or whole-grain cereal, and bread or cereals with nuts and seeds.


Dried peas, dried beans, lentils, and any other legume regardless of preparation method.

Nuts and seeds

Walnuts, almonds, fennel, sesame, sunflower seeds, and other nuts and seeds, as well as chunky nut butter.


Salad dressing containing nuts and seeds, junk food.


Unrestrained soups, pea soup, corn soup, dried bean soup, lentil soup, and chili soup.


Coconut, any dessert containing nuts, seeds, red or purple dye, and any dessert made with whole grain flour and dried fruits.


Fruit or vegetable juices containing pulp and beverages with red or purple dye.

Other foods to avoid

Popcorn, jam, marmalade, olives, pickles, relishes, and stone-ground mustard.

Foods containing dyes are on the to-avoid list because the hues can discolor the colon’s lining. As a result, visibility in the colon is significantly decreased.

During this time, patients also need to stop taking their vitamins and other dietary supplements they may be using.

Although avoiding certain foods is important for a colonoscopy procedure, some people don’t adhere to these instructions. For instance, a study from the journal Medicine found low compliance with diet instructions. In fact, consuming certain foods was the main reason for failed bowel preparation for the procedure (1).

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What foods can you eat before a colonoscopy?

Two and three days (or in some cases, five days) before colonoscopy, you can eat a low-fiber diet. This diet includes:

  • Milk and dairy (except yogurt mixed with nuts, seeds, and fruits)
  • Low-fiber cereal or grains with refined white flour 
  • Meat (except tough meat with gristle)
  • Fruit juices without pulp, applesauce, ripe honeydew or cantaloupe, peeled apricots or peaches, cooked or canned fruit (seedless and skinless)
  • Cooked or canned vegetables (peeled), skinless potatoes, seedless and skinless cucumbers
  • Desserts such as custard, ice cream, plain pudding, sorbet, cakes, or cookies made with plain white flour 

Low-fiber diet stops a day before the procedure.

A day before the colonoscopy, patients need to consume clear liquids only. Good examples are clear broth or bouillon, clear juice, e.g., white grape or apple, and clear soft drinks or sports drinks. Other foods include black tea or coffee, popsicles, and Jell-O. 

Why do you need to adjust your diet before a colonoscopy?

You need to adjust your diet before a colonoscopy because the body needs time to eliminate waste from the colon. Evidence shows bowel prep by adjusting the diet leads to reduced total colonoscopy procedure time, lower costs by preventing canceling or rescheduling procedures, and increased performance with the instrument (2).

Your colon needs to be clear so the doctor can successfully perform a colonoscopy. Otherwise, they would have to reschedule the appointment. That means you need to go through prep again. In many cases, this also translates to higher costs of the procedure.

Remember that high-fiber foods are often undigested when they reach the colon. As a result, they can interfere with the examination process. Doctors need optimal visibility during the procedure. 

When to stop eating before the colonoscopy?

Doctors usually advise patients to stop eating solid foods 24 hours before the procedure. During this time, patients stick to a clear liquid diet for all meals of the day (breakfast, lunch, and dinner). 

Since you’re fasting the day before the procedure, you need to stay hydrated. That’s where the abovementioned clear liquids step in.

In some cases, however, patients may be allowed to consume easily digestible foods 14 to 16 hours before the procedure. Some doctors may allow it if a person cannot fast for 24 hours. 

Consult a doctor regarding this subject. Stick to their instructions and avoid eating anything unless a doctor says it’s okay. 

Two hours before the procedure, you shouldn’t drink anything. Not even water. Patients who drink before colonoscopy risk getting sick or breathing vomit into their lungs. 

Some hospitals or clinics require patients to stop drinking fluids longer than a few hours before the procedure. The instructions you receive will also contain information about this no-beverage window. 


Proper preparation before a colonoscopy procedure is crucial. Preparation revolves around dietary adjustments. 

Five days before the procedure, patients need to stop eating high-fiber foods and consume a low-fiber diet instead. 

A day before the colonoscopy, patients eat no solid foods. Dietary adjustment is necessary to ensure optimal visibility. For that reason, it is crucial to adhere to your doctor’s instructions.

Explore More

what to eat after colonoscopy

What To Eat After a Colonoscopy.


  1. Nam, Seung-Joo et al. “Impact of diet restriction on bowel preparation for colonoscopy.” Medicine vol. 97,41 (2018).
  2. Bechtold, Matthew L et al. “Optimizing bowel preparation for colonoscopy: a guide to enhance quality of visualization.” Annals of gastroenterology vol. 29,2 (2016).

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