First to Sharla: my gyne recommends Designs for Health brand and I use them quite a lot. Your doc can set you up with an account and you can buy direct from their website although my acupuncture doc also carries it if I need to pick up locally.
Interesting colonoscopy prep observation: I usually do not eat a lot of salt or sugar. Pretty much the only calories on this liquid diet prep are from sugar and, unless you are REALLY careful, the broth you buy is VERY salty (what I bought at a regular store for DB last week had like 100% of RDA in one box). Starting on liquid yesterday, "eating" these things I am not used to anymore, I noticed that the first taste wakes up my taste buds like "wow, a party in my mouth", but after about 3 sips, I literally cannot taste the flavor of the "food" AT ALL. It kills my taste buds. So, no, this is not fun. ;-)
I don't love the sugar spikes either...but I've got to have something in my system because I am used to eating every few hours and get nauseous and weak if I don't.
For those of you doing prep in future, try the Trader Joe's low sodium broth: it's got less than 1/5 of the regular grocery store's sodium and, otherwise, the nutrition information is identical. I'm looking forward to that for lunch and dinner.