I have a problem with hypoglycemia. I was very concerned about the liquid diet the day before my first colonoscopy about 8 years ago. The doctor insisted I'd be fine on clear liquids. I passed out in the bathtub and later had a seizure on the couch. Needless to say, I refused to repeat that.
I ended up needing another colonoscopy a few years ago but I couldn't find a GI interested in helping. They said if I wouldn't do their prep, they wouldn't do the precedure. I explained my previous experience but they wouldn't believe me. I finally found a doctor that was willing to experiment. I found something called Nutra-Prep and Lo-So Prep online. Nutra-Prep is a box of low residue food you can eat the day before your precedure. Lo-So Prep is 4 pills, 8 oz of fluid, and a suppository.
It turned out that I had a tumor near my IC valve. If they had found it the year before when I first tried to have a colonoscopy, they could have removed the tumor. Since my diagnosis was delayed, they had to remove my IC valve. I used Nutra-Prep for all 4 colonoscopies plus for the surgery. My surgeon was nervous about this prep but after looking at the pictures and talking to the two GI's that had done my colonoscopies (original doc + second opinion), she agreed. The surgery went well, I was clean.
I had to have another coloscopy a few months ago, my new GI refused to do it unless I followed their prep. I showed him the info on my prep plus the pictures from my last colonoscopy. Still he refused. His nurse insisted I was making up the story about the seizure, anyone would be fine on a liquid diet. I wasn't going through that again so I agreed do their prep but I did mine anyway. Afterward, when the nurse told me I was really cleaned out, I told her about the Nutra-Prep. She said it's only the overweight people that have trouble on a liquid diet and they are the ones who could stand a day without food.
Anyway, if you have trouble with a liquid diet, check out Nutra-Prep. If I had known about this sooner, it would have saved me my intestines.
PS I have no connection to the Nutra-Prep company, I just want to spread the word about their product. It's used by John's Hopkins Hospital so that should give it some respectability.