I would have to add that the fasts of Moses and Jesus were a little more miraculous than most.
I believe that they were both dry fasts. Moses' fast was definitely described as dry and was most likely following at least one other 40 day fast (so two subsequent 40 day fasts and some believe three), as you may recall, the first time he came down the mountain with the commandments he found the Israelites worshiping the golden calf. He then broke the tablets and had to return to the top of the mountain and start over again.
I would download and read the entire Shelton book that Chris linked above. Then you will have a better idea if fasting is safe or not. Never mind all of us here on this forum that do it on a regular basis and have found relief from major illness.