It will also be important to eat a low-fiber diet in the days leading up to a colonoscopy, a clear liquid diet the day before, and stop all liquids several hours before the appointment.

[15] All subjects were instructed to consume a low-fiber diet for 2 days prior to colonoscopy and were given the option of consuming a PEG-based preparation using one of the following dosing ...

You'll need to alter your diet a few days ahead of your colonoscopy. Usually, that means eating foods low in fiber for two to ...