I have seen that video on Youtube few months ago.
She took MSM few times daily during the whole fast. So, Chris is right, it was not water only.
Also, she was having regular exercise and was working, if I remember well. The way it worked for her is not necessarily the way it can work for other people - energy-wise and benefit-wise. I doubt there was much health benefit, not to mention there was a lot of risk health-wise, other than the obvious weight-loss.