I know that there are a lot of negative responses to fasting. One thing that must not be left in the dust is the fact that many people have done it and still do it for religious reasons, not just health. If the big guy, Jesus, did it, then we're supposed to follow in his foot steps. He did it as a personal dependency on God not health. You should look at the history on this. There is alot to be learned.
One thing I have to ask... have those scientists and nutritionists ever done fasts themselves?
If you're on a fast like this you're still getting nutrition. That means it would have to take a very long time for our bodies to start eating away at themselves. I also don't hear of any retched statistics about vegetarians and vegan vegetarians dying at the drop of a hat. Also remember, this is fast for a specific duration of time, not the only way that we will forever get nutrition.