The first time I did this fast I did it because I had two episodes of sciatica in a month and realized that both episodes were triggered by binge eating of junk food and sugar. I researched the issue and found out much to my surprise that diet could trigger sciatica.
Since my first fast 15 day, I have never had sciatica again, also I was suffering from edema, that also has disappeared. I did lose some of the weight that I had put on over the summer and that has stayed off, but nothing matches how great, awake, energised and clean I feel. My skin has changed. And once I clean out with a fast it is much easier to maintain healthy eating.
If you are having doubts I suggest doing research and asking these kind of questions before embarking.