You need to fast for the 12-16 hours before 6:00 am. So stop eating between 2:00 to 6:00 pm the day before. When you wake up at 6:00 am, eat a healthy breakfast.
I think this is very early research and not really applicable.
Staying awake during the fast isn't necessary.
Carbs do that (e.g. potatoes). Try eating proteins and greens only instead and see if it still makes you sleepy.