Pre-Colonoscopy Dietary Preparation

Dietary Recommendations

For optimal bowel preparation before a colonoscopy, patients should follow a low-residue/low-fiber diet on the day before the procedure, avoiding high-fiber foods such as cereals, beans, peas, nuts, seeds, and raw or dried fruits and vegetables, as recommended by the American Gastroenterological Association 1
Limit dietary modifications to the day before colonoscopy for patients at low risk for inadequate bowel preparation, according to the American Gastroenterological Association 1
Follow a low-residue/low-fiber diet for early and midday meals on the day before colonoscopy, as suggested by the American Gastroenterological Association 1
Avoid high-fiber foods, such as cereals, beans, peas, nuts, seeds, and raw or dried fruits and vegetables, on the day before colonoscopy, as recommended by the American Gastroenterological Association 1

Discontinue iron supplements at least 7 days before colonoscopy to prevent dark, sticky stool that can obscure detection of polyps and lesions, as advised by the American Gastroenterological Association 2
Iron residue can compromise diagnostic accuracy by obscuring detection of polyps and lesions, according to the American Gastroenterological Association 2

Medical conditions that increase the risk of poor bowel preparation include cirrhosis (OR 3.4), Parkinson disease (OR 3.2), dementia (OR 3.0), diabetes (OR 1.8), and constipation (OR 1.3), as reported by the American Gastroenterological Association 3, 4
Additional days of dietary restrictions beyond one day before colonoscopy confer no benefit in bowel preparation adequacy, according to the American Gastroenterological Association 3, 4
Patients find 1-day diet restriction more tolerable and easier to comply with compared to longer durations, as noted by the American Gastroenterological Association 3, 4

Unnecessarily restricting diet for more than one day before colonoscopy can reduce compliance without improving outcomes, as warned by the American Gastroenterological Association 1
Failing to discontinue iron supplements at least 7 days before the procedure can compromise diagnostic accuracy, as cautioned by the American Gastroenterological Association 2

The American Gastroenterological Association recommends a low-residue/low-fiber diet for early and midday meals the day before colonoscopy, and switching to clear liquids for the evening meal 5, 6
For split-dose bowel preparation regimens, no specific dietary restrictions are necessary more than one day before colonoscopy 5

Patients at higher risk for poor bowel preparation, such as those with prior inadequate preparation, history of constipation, use of opioids, diabetes mellitus, or spinal cord injury, should consider additional bowel purgatives 7

The American Gastroenterological Association strongly recommends split-dose administration for all patients, with the second portion beginning 4-6 hours before colonoscopy and completing at least 2 hours before the procedure 5, 8