How To Prepare For A Colonoscopy

Before your colonoscopy you will be given instructions on how to prepare for your upcoming procedure. These instructions will provide you with a clear timeline that tells you when to stop eating certain foods and any medication that may cause complications during the procedure. You will also be given a list of clear liquid foods you are allowed to eat one day before the procedure. It is very important that you follow the bowel preparation instructions to have a successful outcome. If you do not fully cleanse your bowels there is an increased risk that your gastroenterologist will miss a polyp or other abnormal tissue findings and the procedure will take longer to complete.

The information in this article is intended to inform you about your procedure and is not intended as an instruction protocol for you to follow before your colonoscopy. Do not follow any instructions from outside sources. Only follow the instructions provided by the healthcare provider who is performing your colonoscopy.

What can I eat, drink, do, or not do before a colonoscopy?

Preparing for your colonoscopy can make many people anxious due to the dietary restrictions and inconvenience of clearing the bowels the day before the procedure. If you are confused about what you can and can not eat or drink before the procedure and what to expect, be open with your doctor and ask any and all questions that cross your mind. It is extremely important that you follow the instructions closely to avoid any complications during the procedure and give your gastroenterologist a precise view of your intestinal lining. 

The following is a timeline and diet plan to help prepare you for your colonoscopy:

A few days before procedure

Some foods will be retained in the lining of the intestine for many days. You are advised to stop eating these foods several days before your procedure. Residual food particles can reduce the clear visualization of the colorectal lining and are more difficult to suction during the colonoscopy.

Do not eat the following:

  • Seeds or nuts, such as sunflower seeds, almonds, and cashews
  • Whole grains, including barley, flaxseed, brown rice, and quinoa
  • Fruits with small seeds, including strawberries and raspberriesGrapes
  • Tomatoes with skins
  • Peas
  • Onions
  • Beans
  • Celery

1 day before the procedure 

One day before your colonoscopy you will be asked to stop eating all solid foods and be on a clear-liquid diet.The definition of a clear liquid is one that you can see through with no pulp or solids present. For instance, if your liquid is in a bowl or glass and you can see right through the substance then it is considered a clear liquid. The liquid can be clear, yellow, green, orange, or blue. You should avoid all clear liquids that are red or purple colored. Red and purple dye interferes with your colonoscopy results because the color can mask the lining and disguise abnormal tissue growths. 

Liquids you are able to take include:

  • Broth, including vegetable, chicken, or beef
  • Fruit juices (no red or purple juices)
  • Popsicles (except red or purple)
  • Jello™
  • Soda
  • Sports drinks
  • Ensure Clear™
  • Black coffee or tea (DO NOT add any creamer)
  • Clear protein supplement 

The morning of the procedure

You may be advised the following a few hours before your colonoscopy:

  • No eating
  • No drinking
  • No chewing gum or sucking on hard candy
  • Nothing by mouth, including water

What can happen if I do not follow the restrictions?

  • Be sure to read your colonoscopy prep instructions completely as soon as your doctor gives them to you. Call your doctor if you have any questions about the preparation. There are several reasons to adhere closely to the instructions your healthcare provider gives you before your colonoscopy. These include:

    • Improper bowel prep can delay your procedure and complicate doctor’s evaluation
    • Missed polyps and cancers have been attributed to poor visualization due to not following restrictive diet
    • Having an empty stomach reduces risk of aspirating vomit into lungs during sedation
    • Chewing gum or tobacco less than three hours before your procedure increases risk of anesthesia complications because of increased stomach contents
    • Your doctor may cancel your colonoscopy if there are food residue or dyes found on intestinal lining

Do any certain groups (e.g. people with comorbidities, etc.) need to follow different protocols?

Be sure to communicate with your healthcare team about any questions or concerns you have about preparing for your colonoscopy. Some questions you may want to ask include:

  • Are there medications I should stop taking before my colonoscopy?
  • Can I continue to take medications that are not blood thinners before procedure?
  • What clear liquids are acceptable the day before my colonoscopy?
  • Can I continue my clear liquid diet after I take the bowel preparation laxative?
  • Why do I have to limit certain food types a few days before my procedure?
  • Why can’t I drink alcohol the day before my procedure?
  • Can I smoke cigarettes or cigars the day before my procedure?

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