Depends what you eat. If you eat 5 mini cliff bars every three hours, that’s a terrible idea - your insulin will always be high, but you will have no glycogen, so your body will reduce caloric expenditure.
If you eat a chicken breast with a lot of greens in one meal, that’s not a problem at all - it is basically OMAD.
Sometimes you just have to cope the best you can till you get there. Or fake it till you make it. If you have never fasted before 3 days is going to be tough. May want to start small and work your way up. You’ll be fine. Good luck 🍀!