all of that is true, BUT...
1. you are getting sugars from both the lemon and the maple syrup so you are getting a constant supply of energy...that means your glycogen stores are not really being used up..if they were you would pass out so that your body could divert as much as possible to your brain and eyes.
2. if you fast for a very long time your body will start to feed on itself, but its going to start with your muscles then move onto your organs..if you get to the point where your body is feeding on your organs then your going to be so thin and weak becuase your muscles have wasted away that you would notice something is wrong..unless of course you have a body image disorder, but thats another issue.
3. The Master Cleanse is supplying you with all the nutrients AND calories you need.

people who say that fasting is bad for you have usually never been on a fast and/or have not takent he time to really research it. they just assume people are starving themselves. a proper fast will keep you hydrated (this is way more important than food) and it should give you nutrients.
there are many types of fasts and many different reasons to do them...some good some bad. you cant generalize becuase everyone is different

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.

Ketosis will not rob the major organs first. After the glycogen supplies in the liver are exhausted the body begins to break down adipose tissue (fat)and produce ketones that actually feed the brain and heart. The only part of the body that is really at risk when in full ketosis is the muscles. Muscles must have glucose for fuel and will begin to break down and consume themselves. However this only happens when the body has totally exhausted it glucose and extreme demands are being put on the muscles. That is the reason water only faster are told to stay in bed and rest. With The Master Cleanse the body is getting plenty of glucose when the sugars in the Maple syrup are broken down. While the body will probably produce some ketones, especially in very long fasts, or when the amount of syrup is drastically cut, there is little chance of the body starting to consume itself. Muscle wasting will not be a problem during a Master-Cleanse unless the faster does far too much exercise.

The human body also has the wisdom to first break down and use toxins, abscesses, fungi, and even tumors for fuel. Also the metabolism automatically slows down and the body does not require as many calories (fuel) to stay alive. Ancient humans frequently had to endure long periods of scarcity of food. Modern humans still have the capacity to safely go without food for extended periods of time when necessary. While extremely long fasts are very stressful on the body, and eventually start causing problems instead of healing them, there is no reason to think a short or even moderately long fast (no more than 40 days) will cause lasting problems. The chances of heart or liver damage are practically nil unless there were some pre-existing problems. Any fast, including The Master Cleanse should only be done when the individual is educated, prepared and aware. Fasting is a cleanse, not a diet. s long as one has a realistic view of how long to fast, what to expect, and know when it is time to stop, fasting is safe and effective.