I regularly fast intermittently and have fasted many times up to 10 days. The clarity of mind after the third day is remarkable. I often think of fasting in a spiritual sense. God word speaks of fasting and Jesus sets a great example. I believe it brings us closer to God. In the Old Testament, part of the commands surrounding the temple and visitation thereof was to prepare and consecrate themselves beforehand. Back then it was in the form of physical cleanliness. They were told to wash themselves physically and follow the laws of cleanliness. Consecration is quite literally to clean yourself. To have more deep and effective communication with God you must consecrate yourself. Your body is now the temple. I believe being cognizant of your current struggles with sin and asking forgiveness clears and declutters our communication path with God. It is my opinion that fasting does this physically as well. There is very noticeable mental clarity after the third day of fasting. Your brain, arguably the tuning tool that connects your heart and mind to the spiritual realm, operates better when fasting. I believe fasting consecrates us in a very physical and spiritual way. It is a mechanism that brings us closer to God, supercharging our communication and prayers.