A colonoscopy is a diagnostic procedure that allows a physician to examine the lining of the large intestine, or colon, using a flexible tube with a camera. For this examination to be successful, the colon must be completely empty and clean, which requires rigorous bowel preparation. This preparation is mandatory and involves specific changes to your diet to ensure a clear view of the colon walls. Dietary restrictions begin several days before the procedure and are necessary to achieve a successful screening.
The Specifics of Cheese and Residue
Eating cheese two days before a colonoscopy is generally not recommended as it can compromise the necessary preparation. Cheese is a dairy product high in fat and protein, components that take a significant amount of time to be fully digested. These undigested solids contribute to fecal bulk, also known as residue. Foods that leave substantial residue behind can obscure the view of the colon lining, which the preparatory diet aims to prevent. For this reason, medical protocols advise against consuming all dairy products, including cheese, during the days leading up to the procedure.
Guidelines for the Low-Residue Diet
The low-residue diet is a temporary eating plan designed to significantly reduce the amount of undigested material that remains in the gastrointestinal tract. This diet is typically initiated two to three days before the colonoscopy to decrease the frequency and volume of stools. The goal is not to stop bowel movements completely, but to minimize the bulk that the powerful laxative preparation will need to clear.
This dietary phase permits easily digestible foods that are low in fiber, which is the main source of residue. Allowed items include refined grains like white bread, white rice, and plain crackers. Lean, tender meats such as chicken, fish, and turkey are also permitted.
You can also consume cooked vegetables without skins or seeds, such as peeled potatoes or strained vegetable juices. Conversely, all high-residue foods must be avoided because their components pass through the colon largely undigested. This includes whole grains, nuts, seeds, popcorn, and raw fruits and vegetables. By focusing on low-fiber and low-fat foods during this period, you help reduce the fecal matter that could otherwise hide polyps or other abnormalities during the examination.
The Final Step: Transitioning to Clear Liquids
Following the low-residue diet, the preparation protocol requires a complete transition to a clear liquid diet, which typically begins about 24 hours before the procedure. At this stage, the consumption of all solid food must cease. A clear liquid is defined as any liquid you can see through, and it must contain no solid particles.
Appropriate clear liquids include water, clear broth, apple juice, white grape juice, and light-colored sports drinks. Red or purple liquids are usually avoided as their coloring can be mistaken for blood in the colon. Beverages containing milk or cream, including dairy and non-dairy substitutes, are strictly prohibited in this final phase. Maintaining hydration with these clear liquids is important, as the laxative preparation will cause significant fluid loss.