The question about going on a juice fast came up, and one person advised cleaning up your diet and eliminating toxic foods ahead of time before the fast would make it easier. That reminded me of an incident when I was in college.
During my senior year in music school, some of my housemates decided to "go on a diet" on a certain day. So the day before it was to start, they decided to pig out on all the junk food they would not be allowed to eat during their "diet." They spent all day eating hot dogs, bologna, ice cream, cookies, candy bars, pizza, potato chips, soda, you name it. All day long pigging out on purpose. I kept on asking them why not just take it easy that day instead of putting all that junk into their systems. They said "Where's the fun in that? We have to load up on all this junk because we can't have it during our 'diet'."
It was pretty gross to witness, as you can imagine. They felt so sick the next day, the first day of their "diet," and didn't want to face having sprouts and juice for breakfast to start things off. I could tell they wanted to break out the package of bacon instead.
This "diet" lasted about 5 or 6 days, then it was back to the status quo.