It is always adviceable to do a round of probiotics to replenish the intestinal flora after any fast. Breaking any fast properly and gradually is very important. If you fast and 3 days later you go out and eat a cheese burger or beer and pizza or a goat you're gonna have problems. "Cleansing" just helps to take the junk out so the system operates more efficiently and then it can heal itself. Any actual healing and cure is totally dependant on what you put back in AFTER you fast. If you go back to your old habits you will have the same problems.
Fasting has been around for hundreds more likely thousands of year and even now modern medicine has taken notice and there are all kinds of actual medical studies that verify the benefits. If you do the max number of drinks in the MC you are taking in 1200 calories and lots of carbs and minerals so there is no chance of any muscle waste. Do your own research on fasting and how it actually works. Google is your friend.
10 days is just a minimal fast. To get down to the cellular level you need to go past 14 days. Read the Detox Stages in the FAQs