I’m no nutritionist, but I’m fairly certain I’d be unable to survive on 5600 calories a week / 800 calorie a day diet for any long period of time. Maybe you can survive that under the most ideal conditions like if you were 4’11”, weighed 85 pounds, and never removed your ass from the couch. Me at 6’3”, weighing 220, and living a fairly active lifestyle that would have me looking like a holocaust victim in just a few weeks.