Can I Eat 24 Hours Before a Colonoscopy?

Medically Reviewed on 5/20/2021
colonoscopy
Before a colonoscopy, you should avoid solid foods for at least 24 hours

Preparing for a colonoscopy can be a hassle. Your colon has to be as empty as possible so that your doctor can look for polyps and other signs of cancer. So while it’s an exam most people dread, it’s worth the effort involved.

Before a colonoscopy, you should avoid solid foods for at least 24 hours and stick to a clear liquid diet for breakfast, lunch and dinner. Ask your doctor about what you can have and when, since in some cases you may be allowed to eat easily digestible foods up to 14-16 hours before the procedure if you aren’t able to fast for long.

What should you avoid having before a colonoscopy?

Following a clear liquid diet means you should avoid eating any solid foods, including: 

  • Bread, grains, rice or cereals
  • Soups with chunks of food
  • Meat
  • Milk or dairy products
  • Vegetables
  • Fruits

Liquids to avoid include:

  • Milkshakes
  • Coffee with cream
  • Pineapple juice
  • Orange juice
  • Milk or dairy drinks
  • Alcohol

Clear liquids you can have include:

  • Water, including mineral water
  • Soda
  • Club soda
  • Black coffee with no cream or milk
  • Sports drinks with electrolytes
  • Apple juice
  • Tea without milk
  • Honey
  • Flavored gelatin
  • Clear broth

What’s involved in preparing for a colonoscopy?

Plan ahead

Your doctor will give you instructions when scheduling your colonoscopy. Make sure to read them carefully and talk to your doctor if you have any questions.

Stock up on these items before the procedure:

Change your diet

Eating light foods 3-4 days before the procedure can help ease the colon-cleansing process. Low-fiber foods are generally recommended because they are easy to digest.

You can eat:

  • White bread, pasta and rice
  • Well-cooked vegetables without skin
  • Fruit without skin or seeds
  • Lean meat, chicken or fish
  • Eggs

Do not eat:

  • Seeds, nuts or popcorn
  • Fatty foods
  • Tough meat
  • Whole grains
  • Raw vegetables
  • Fruit with seeds or peel
  • Corn, broccoli, cabbage, beans or peas

Stop taking vitamins or other supplements at this point. If you are taking blood-thinning or other over-the-counter anti-inflammatory medicines, make sure to ask your doctor about whether you should stop. 

Fast for 24 hours

As discussed above, you should stop eating solid foods a full day before the procedure. Stick to only clear liquids. 

Take laxatives

The night before your colonoscopy, you will need to take strong liquid laxatives, usually a half gallon, to clear your digestive tract. Six hours before the procedure, you will need to take another half-gallon of liquid laxative. 

Since laxative solutions often have an unpleasant taste, you may want to mix yours with a flavored sports drink or powdered drink mix.

Once the laxatives start working, you will experience frequent, forceful diarrhea. You may also experience:

Stay calm

The purging process can be rough. Here are a few tips to make yourself as comfortable as you can:

  • Stay in the bathroom and entertain yourself by reading a book or listening to music.
  • Apply diaper cream before diarrhea starts.
  • Use medicated wet wipes to clean yourself.

Once your bowels have been cleansed, your stool will look like urine or clear water. This means you’ve completed the process and your colon is ready for the colonoscopy. 

While it’s not easy, remember that the better you prepare, the faster the procedure will be, and you may not have to do it again for another 10 years.

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Medically Reviewed on 5/20/2021
References
WebMD. How to Prepare for a Colonoscopy. https://www.webmd.com/colorectal-cancer/prepare-for-colonoscopy

UCLA Health System. Preparing for Your Colonoscopy. https://www.uclahealth.org/Workfiles/brochures-programs/preparing-colonoscopy-en.pdf