Just went through this and you would think my dr who is a motility specialist would have known better. Had me do a 3-day low residue diet which is basically high-carb no-fiber prior. What it did was totally constipate me so I was behind going into the prep. Did the jug of Golytely. Thought I was good. Nope. Couldn’t get all the way in. Told me my colon was like a roller coaster. Next time, no low-residue, two-day prep. More Golytely. So talk to your doc about this Before!