What happens to you aspiring only when your bushwalking anorexics on a long trip ? Fasting when exerting heavily is a finite process
I'm with Icefest - lay day equals pigout big time. (I don't fold over pages either - really agonized about the possible damage to a hard back that I carried recently

Perhaps that's one reason why I always have sufficient of that for which books are sometimes substituted)
My 200 grams of scroggin never lasts the day.
Food is fuel, people. No fuel-no fire, No fire - no energy.
Low on fuel, particularly toward the end of a hard day can be dangerous. I have flirted with this scenario a few times.