My dr uses the most "humane" prep ever. You can eat a small breakfast the day before, a plain turkey sandwich for lunch and then the rest of the day clear liquids. At 6pm drink a bottle of magnisium citrate. At 8pm take 3 ducolax tablets. At 5am use a ducolax suppository.
I wasn't starving and I was very cleang for the test... he said after 40 years of being a Dr and trials of different preps, he found this one to be the best for his patients.