I'll only address the 24 hr. liquid diet before the colonoscopy (had an upper endoscopy at the same time), it wasn't as difficult as I'd thought it would be. I drank lots of my preferred beverages- unsweetened decaf green tea & seltzer water, Edy's outshine fruit bars-pineapple & lime. I only tried my daughter's Izze fruit/ seltzer juices afterwards, wish I had discovered them earlier. I wasn't hungry (10 hrs. In, you start the prep, & that occupies your thoughts).
The prep is much worse than the procedure (I won't go into details), which was a breeze, in comparison- all done for a few years , at least. I ate a good meal right after I came home, then napped for several hours.
I took most of my meds before the procedure (skipping Adderall & Metformin), my bp was low/normal & blood sugar was 100. I am thankful that everything went smoothly (no pun intended, I don't remember a thing).