From my perspective, due to sleep time is all covered during the fasting period. When sleeping, it would be neither activities nor water flowing in your body. Therefore fluids are relatively thick inside your body when you wake up. Gallbladder has to stand by 4-5 hours to secrete bile before encountering food. Groups with high risk of gallstones are prone to produce gallstones. It seems to me that eating the last meal of the day as early as you can. For instance at 6 or 7pm, you'll still be doing your usual activities and staying hydrated. By the way they do 12 hours fasting so these are still differentiated. Not sure if I’m wrong.