Preprocedural dietary restrictions have been identified as a common reason potential candidates for colorectal cancer screening do not undergo colonoscopy as recommended.

To study whether a low-residue diet impacts bowel preparation with oral sulfate solution.

Endoscopist blinded, prospective, randomized controlled trial.

Community-based outpatient ambulatory surgical center.

Patients scheduled for outpatient colonoscopy.

Subjects were randomized to ingest either a low-residue diet of specified foods for breakfast, lunch, and snack or a clear liquid diet the day before the colonoscopy.

The quality of the bowel preparation was assessed using the Boston Bowel Preparation Scale. Subject satisfaction with bowel preparation, diet, and severity of side effects was measured by a visual analog scale.

Two hundred thirty subjects were recruited (114 clear liquid and 116 low residue). Mean preparation scores were not statistically different in either their segmental scores or total score. Subjects in the low-residue arm reported significantly higher satisfaction with bowel preparation medication, diet, and entire preparation process. Observed rates of side effects were low, and there was no statistical difference between the two groups. The rate of procedural cancellation was significantly higher in the clear liquid group compared with the low-residue group (20% vs 9%, P = .03).

Single-center study.

A low-residue diet did not impair the quality of bowel preparation achieved with split-dose oral sulfate solution but did improve patient satisfaction.