Navigating a Low-Residue Diet Before Your Colonoscopy

If you are scheduled for a colonoscopy, you may be wondering how to prepare for it. A colonoscopy is a procedure that allows your doctor to examine the inside of your colon (large intestine) and rectum for any abnormalities, such as polyps, tumors, or inflammation. To get a clear view of your colon, you need to follow a special diet before the procedure. This diet is called a low-residue diet, and it aims to reduce the amount of stool and waste in your colon.

Table of Contents

• What is Colonoscopy?
• What is a Low-Residue Diet?
• How to Follow a Low-Residue Diet?
• Is There a Quick Way to Identify Low-Residue Foods?
• Is Liquid Food Equivalent to a Low-Residue Diet?
• Conclusion

What is Colonoscopy?

A colonoscopy is a procedure that uses a thin, flexible tube with a small camera and light at the end, called a colonoscope, to examine the inside of your colon and rectum. The colonoscope is inserted through your anus and gently moved along your colon. The camera sends images to a monitor that your doctor can view in real time. Your doctor can also take samples of tissue (biopsies) or remove polyps (growths) during the procedure.

A colonoscopy can help diagnose various conditions that affect the colon and rectum, such as:

• Colorectal cancer
• Polyps
• Inflammatory bowel disease (IBD), such as Crohn's disease or ulcerative colitis
• Diverticulitis (inflammation of pouches in the colon wall)
• Bleeding or anemia
• Changes in bowel habits or unexplained weight loss

A colonoscopy can also be used as a screening test for colorectal cancer, which is the third most common cancer and the second leading cause of cancer death in the United States. The American Cancer Society recommends that people at average risk of colorectal cancer start regular screening at age 45, or earlier if they have a family history or other risk factors. Screening can help detect colorectal cancer early, when it is easier to treat and cure.

What is a Low-Residue Diet?

A low-residue diet is a type of diet that limits the intake of foods that contain rough or insoluble fiber, which are parts of plant foods that are not digested by your body. These foods include whole grains, nuts, seeds, fruits, vegetables, beans, and legumes. Fiber adds bulk and water to your stool, making it softer and easier to pass. However, before a colonoscopy, you want to minimize the amount of stool and waste in your colon, so that your doctor can see the lining of your colon clearly.

A low-residue diet typically allows less than 4 grams of fiber per day. It also restricts other foods that may leave residue or particles in your colon, such as dairy products, red meat, spicy foods, fried foods, alcohol, coffee, and tea. A low-residue diet is not meant to be followed long-term, as it may cause nutritional deficiencies and constipation. It is only recommended for a short period of time before a colonoscopy or other medical procedures that require a clean colon.

How to Follow a Low-Residue Diet?

When adhering to a low-residue diet, aim for a balanced approach, opting for "low-residue, low-fiber, easily digestible" foods. Cooking methods should primarily include steaming and boiling, while avoiding raw, fried, deep-fried, grilled, or heavily stewed foods.

Staple Foods

Staple foods are the main source of carbohydrates and energy in your diet. They include grains, cereals, breads, pasta, and potatoes. When following a low-residue diet, you should choose refined or processed staple foods that have less fiber and are easier to digest. For example:

• White rice, white bread, white pasta, white flour tortillas
• Cornflakes, rice krispies, cream of wheat, oatmeal (not instant)
• Plain crackers, saltines, pretzels
• Peeled and boiled potatoes, sweet potatoes, yams

Avoid whole grains and high-fiber foods such as brown rice, whole wheat bread, bran cereals, quinoa, barley, buckwheat, popcorn, and granola.

Legumes and Their Products

Legumes are a group of plant foods that include beans, peas, lentils, soybeans, and peanuts. They are rich in protein, iron, folate, and fiber. However, they can also cause gas and bloating in some people and increase the residue in your stool. Therefore, you should limit or avoid legumes and their products when following a low-residue diet. For example:

• Avoid beans (black beans, kidney beans, pinto beans), peas (green peas, split peas), lentils (red lentils, green lentils), chickpeas (garbanzo beans), hummus
• Avoid soybeans (edamame), tofu (soybean curd), tempeh (fermented soybean cake), soy milk
• Avoid peanuts (groundnuts), peanut butter

If you do eat legumes occasionally, choose canned or cooked ones that are soft and well-mashed. You can also remove the skins or hulls of the legumes to reduce the fiber content.

Fish and Meat

When choosing meat, avoid consuming meat that is not peeled, free of tendons, or soft bones to reduce the residue of animal collagen in the colon. Can eat: Lean meat or fish without skin and tendons. Avoid: Fish with skin and tendons, fatty meat, pork belly, beef tendons, fried chicken cutlet.

Dairy Products

Dairy products, due to their casein content, form clots when combined with stomach acid, making them challenging to digest. Lactose in milk, if not completely digested, creates a food source for intestinal bacteria, promoting their proliferation and increasing stool volume, which is not conducive to colonoscopy. Can eat: Commercially available lactose-free, fiber-free, or clear liquid formula supplements. Avoid: Milk, powdered milk, cheese, yogurt.

Vegetables

Avoid vegetables with high fiber content in stems, stalks, and old leaves. Be cautious of vegetables that may stimulate gas production in the intestines. Can eat: Various filtered vegetable juices, chopped tender leaves like spinach and amaranth, peeled and seedless mature melons such as winter melon, cucumber, zucchini, or simmered carrots and daikon radishes. Avoid: Stems and stalks of leafy vegetables, bamboo shoots, celery, asparagus, cabbage, onions, cauliflower, leeks, bell peppers.

Fruits

Choose soft fruits with low fiber and peel and seed them or opt for filtered fruit juice. Can eat: Papaya, cantaloupe, honeydew, watermelon, lychee, grapes, and filtered fruit juice. Avoid: High-fiber fruits like guava, pomelo, dates, pineapple, kiwi, various dried fruits, and unfiltered fruit juice.

Fats and Nuts

Nuts and seeds tend to leave residues in the digestive tract, so it's advisable to avoid consuming them. Various cooking oils, on the other hand, don't have strict intake limitations, but it's essential to be cautious about avoiding frying or deep-frying cooking methods. Can eat: Animal and plant oils and their products. Avoid: Cashews, peanuts, walnuts, almonds, pistachios, sesame, and other nut varieties.

Is There a Quick Way to Identify Low-Residue Foods?

A simple way to determine whether a food is low-residue or not is to consider how long it takes to chew it. Foods that require more chewing time are usually high-residue foods, such as vegetables and fruits that are rich in fiber. Foods that are easy to swallow and digest are low-residue foods, such as tofu pudding and tofu. Of course, there are some exceptions, such as milk, which is a high-residue food.

Is Liquid Food Equivalent to a Low-Residue Diet?

Liquid food does not necessarily mean low-residue food. Many people may think that soupy and watery foods are low-residue foods, but this is not always true. For example, corn soup, pumpkin soup, milk, and unfiltered vegetable and fruit juices are not low-residue foods.

Conclusion

Preparing for a colonoscopy can be challenging, but following a low-residue diet can make the process easier and more comfortable. A low-residue diet consists of foods that are easy to digest and leave little waste in the colon. Some examples of low-residue foods are white bread, rice, eggs, fish, chicken, and clear liquids. Avoid foods that are high in fiber, fat, or dairy products, such as whole grains, nuts, seeds, beans, cheese, and milk. By following a low-residue diet before your colonoscopy, you can help ensure a successful and accurate examination of your colon.