As I am blessed to not have severe gut issues such as the ones that Dr Campbell McBride talks about here, I did Stage 1 for three days and (quite happily) moved on.
On the first day I found that drinking about a quart of chicken broth and another quart of mint tea as well as pretty much only eating really broth-y chicken soup led to lots of peeing. Of course this makes perfect sense, but it wasn’t what I was used to. The fact that I ate -only- chicken soup was a mistake, I think. Just because you are limited to only a few foods doesn’t mean you have to give up variety. I would highly suggest anyone doing the Stage1 Intro make at least two different soups a day for variety.