What is a low residue diet before a colonoscopy?
A low residue diet before a colonoscopy is a short-term, low-fiber eating plan that avoids foods that leave undigested material in the colon, such as whole grains, nuts, seeds, beans, raw vegetables and fruit skins. At United Gastroenterology Associates, the general colonoscopy instructions ask you to follow any low-fiber diet steps on your prep page for a few days before the procedure, then switch to clear liquids the day before, as directed.
Residue is the part of food that the body does not fully digest. Fiber, seeds and tough skins can cling to the colon wall and hide small polyps. When the colon is not clean, small polyps can be missed and the colonoscopy may need to be repeated, which is why the diet and the prep work together. See the practice’s colonoscopy prep instructions and general colonoscopy instructions for your exact timeline.
Your colonoscopy diet timeline
- About 7 days beforeRead your instructions, pick up your prep and call the office about blood thinners, diabetes, GLP-1 medicines, iron or supplements.
- A few days beforeFollow the low-fiber, low residue diet described on your prep page.
- The day beforeSwitch to clear liquids only, as directed, and start your bowel prep at the time shown.
- Procedure dayFinish your prep as directed. Nothing by mouth from 3 hours before arrival, except approved medicines.
What low residue foods can I eat before a colonoscopy?
During the low residue days you can usually eat white bread, white rice, regular pasta, plain crackers and flour tortillas; eggs, tender chicken, turkey, fish and tofu; smooth dairy foods; well-cooked vegetables without skins or seeds such as peeled potatoes and carrots; and soft or canned fruit without skins or seeds, such as applesauce, canned peaches and ripe bananas. Butter, oil, broth and pulp-free juice are also fine.
| Food group | Usually OK during low residue days | Avoid |
|---|---|---|
| Grains | White bread, white rice, refined pasta, plain crackers, flour tortillas, cream of wheat | Whole wheat, brown or wild rice, oats, bran, granola, corn tortillas, popcorn |
| Protein | Eggs, tender chicken, turkey, fish, tofu, smooth peanut butter | Beans, lentils, nuts, chunky nut butters, tough or gristly meat |
| Vegetables | Well-cooked carrots, green beans, peeled potatoes, squash without seeds | Raw vegetables, salads, corn, peas, broccoli, vegetable skins |
| Fruit | Applesauce, canned peaches or pears, ripe banana, pulp-free juice | Berries, dried fruit, fruit with skins or seeds, pineapple |
| Dairy | Milk, plain yogurt, mild cheese, in moderation | Yogurt with fruit pieces, nuts or granola |
| Seeds and extras | Butter, oil, mayonnaise, smooth sauces, gelatin | Chia, flax, sesame and poppy seeds, seeded breads, jams with seeds |
Can I eat flour tortillas before a colonoscopy?
Yes, plain flour tortillas made from refined white flour are generally considered low fiber and low residue, so they are usually allowed during the low residue days before a colonoscopy. Corn tortillas and whole-wheat tortillas contain more fiber and should be avoided. Once you switch to clear liquids the day before, no tortillas or other solid foods are allowed.
Keep the fillings low residue too. A flour tortilla with scrambled eggs, shredded chicken or turkey and a little mild cheese fits the diet. Beans, corn, salsa with seeds, lettuce and raw vegetables do not.
Are tortilla chips low residue?
Most tortilla chips are made from whole-grain corn, which is higher in fiber and leaves residue, so they are best avoided during colonoscopy prep. The same goes for popcorn and corn on the cob.
Can I eat canned pasta like Beefaroni on a low residue diet?
A serving of canned pasta made with white pasta, ground beef and a smooth tomato sauce, such as Beefaroni, is generally considered low residue during the low-fiber days. Choose varieties without beans, vegetable chunks or seeds. Stop all solid food, including canned pasta, when you begin clear liquids.
Have symptoms like these?
Dr. Muhammad Ali Khan, a board-certified gastroenterologist and hepatologist, sees adults at our Katy and Cypress offices, serving patients across Greater Houston.
What foods should I avoid before a colonoscopy?
Avoid high-fiber and hard-to-digest foods before a colonoscopy: whole grains, brown rice, oats and bran; nuts and all seeds, including chia, flax and sesame; beans and lentils; corn and popcorn; raw vegetables and salads; fruit with skins or seeds, berries and dried fruit; and tough meats. These foods leave residue that can coat the colon and make your prep less effective.
Some medicines and supplements also need attention. The practice’s general instructions ask patients to stop iron, diet pills and herbal medicines 7 days before, and to call the office about blood thinners, diabetes medicines and GLP-1 medicines. Do not stop any prescribed medicine on your own.
What can I eat and drink on the clear liquid day?
On the clear liquid day you can have liquids you can see through: water, clear broth, pulp-free apple or white grape juice, sports drinks, soda, plain tea or coffee without milk or creamer, gelatin and popsicles, plus clear protein drinks if your instructions allow them. Do not eat solid food or drink milk, smoothies or juices with pulp. Many instructions also ask you to avoid red, purple or blue colored drinks.
The practice’s instructions note that sugars are fine on the prep day because clear liquids are your main source of calories, and suggest aiming for about 45 to 60 grams of carbohydrates at each meal time, plus broth or other electrolyte drinks for snacks. If you have diabetes, follow the office’s personal instructions about blood sugar and medicines.
Important
Follow the instructions given to you for your specific prep. If anything on this page differs from your prep instructions, follow your instructions. Eating solid food or drinking non-clear liquids on the clear liquid day can lead to your procedure being cancelled. Questions? Call (346) 340-4414.
What does a sample low residue menu look like?
A simple low residue day could be scrambled eggs with white toast and pulp-free juice for breakfast; a turkey and cheese sandwich on white bread or a flour tortilla with chicken broth for lunch; applesauce and plain crackers for a snack; and baked chicken or fish with white rice, peeled mashed potatoes and well-cooked carrots for dinner. Drink plenty of water throughout the day.
- Breakfast: scrambled eggs, white toast with butter, pulp-free apple juice
- Lunch: turkey and mild cheese on white bread or a flour tortilla, cup of chicken broth
- Snack: applesauce or canned peaches, plain saltine crackers
- Dinner: baked chicken or white fish, white rice, peeled mashed potatoes, soft-cooked carrots
- Dessert: plain gelatin or vanilla pudding
Tip: Shop before your low residue days
Buy white bread, flour tortillas, rice, eggs, broth, applesauce, clear juice and gelatin a few days ahead so you are not tempted by high-fiber foods already in your kitchen.
Get answers instead of guessing
Request a visit with Dr. Muhammad Ali Khan at our Katy and Cypress offices. Most major insurance plans are accepted and self-pay options are available.
Why does a clean colon matter?
A clean colon lets the gastroenterologist see the entire lining clearly, which is how small polyps and early changes are found and removed. When residue or stool remains, small polyps can be missed and the colonoscopy may need to be repeated. By the end of a good prep, bowel movements should be liquid, clear or light yellow, and free of solid pieces.
A colonoscopy is one of the most effective ways to prevent colorectal cancer, because precancerous polyps can be removed during the same procedure. Learn more about colonoscopy in Katy and Cypress and screening vs. diagnostic colonoscopy.
Key takeaways
- Low residue foods for colonoscopy are low in fiber and easy to digest, such as white bread, white rice, eggs, chicken, fish and peeled cooked vegetables.
- Plain flour tortillas are generally allowed during the low residue days; corn tortillas and tortilla chips are not.
- Avoid whole grains, nuts, seeds, beans, corn, raw vegetables and fruit skins before your colonoscopy.
- Switch to clear liquids the day before, as directed, and follow your prep page for exact timing.
- A clean colon helps the doctor find small polyps and avoids a repeat procedure.
Frequently asked questions
How many days before a colonoscopy should I eat low residue foods?
Most instructions call for a low-fiber, low residue diet for a few days before the procedure, then clear liquids the day before. Follow the exact number of days on your prep page, since it can vary by prep and by patient.
Can I eat eggs before a colonoscopy?
Yes. Eggs are a low residue food and are usually fine during the low-fiber days. Stop eating them when you switch to clear liquids.
Can I drink coffee before a colonoscopy?
Plain black coffee without milk, creamer or non-dairy creamer is usually allowed as a clear liquid. Stop all liquids at the time your instructions give, which at this practice is 3 hours before arrival, except approved medicines.
Is peanut butter low residue?
Smooth peanut butter is often allowed in small amounts during the low residue days, but chunky peanut butter and whole nuts are not. Check your prep page if you are unsure.
What happens if I eat the wrong food before a colonoscopy?
Call the office at (346) 340-4414 and tell them what you ate and when. Depending on the food and timing, you may be able to continue, or the team may adjust your prep or reschedule so the colon can be properly cleaned.
Can I eat cheese before a colonoscopy?
Mild cheese is generally allowed in moderation during the low residue days. Avoid cheeses with seeds, nuts or fruit, and stop all dairy when you begin clear liquids.
Sources
- NIDDK — Colonoscopy
- MedlinePlus — Low-fiber diet
- MedlinePlus — Clear liquid diet
- MedlinePlus — Colonoscopy
- American College of Gastroenterology — Colorectal cancer
Where to be seen in Katy and Cypress
United Gastroenterology Associates has two offices: Katy, at 23920 Katy Freeway, Suite 555, next to Memorial Hermann Katy Hospital, and Cypress, at 21216 Northwest Freeway, Suite 640, on US-290. Both are open Monday through Friday, 8:30 AM to 5:00 PM, closed for lunch from 12:00 to 1:30 PM, and serve patients from Fulshear, Richmond and across Greater Houston. Call (346) 340-4414 for either office.
Katy office
23920 Katy Freeway, Suite 555
Katy, TX 77494
Memorial Hermann Medical Plaza 1
Next steps
If you are dealing with low residue foods for colonoscopy or any ongoing digestive concern, a focused evaluation can find the cause and start the right treatment. Dr. Muhammad Ali Khan and the team at United Gastroenterology Associates see adults from Katy, Cypress, Fulshear, Richmond, Greater Houston and across Texas. Call (346) 340-4414 or request an appointment today.
If you have severe pain, vomit blood, pass black stools or have chest pain, call 911 or go to the nearest emergency room.
