I did Master-Cleanse for 36 days in 2005 with great results. I also spent 11 days prepping for the fast and came off the fast in 11 days. My goal was 40 days of Master-Cleanse but did not make it the 4 days to hit 40. Before starting the Master-Cleanse I had my Sugar levels drop as low as 55 and 35 two weekends in a row about 2 months prior to starting. I was taking no meds for this but quickly adjusted by drinking juice and kefir for the protein to raise Sugar levels. While doing MC, I had no low blood Sugar problems at all. I did feel like they might try to go low a couple of times but nothing happened. When I felt like this, I would take a tablespoon of Molasses and drink more water. I was menstruating during the fast and took the Molasses for the first 4 days to give me extra iron. I've not had my blood sugar levels drop that low since completing MC fast. I hope some one else with experience chimes in but for me, I had not trouble at all.