It can also be a good idea to not look at screens sometimes, but it's disruptive if that time away from screens is at a time not of your choosing but forced on you by external conditions.
FWIW when I'm eating a very low carb diet with no stimulants, fasting for a day is a complete noop, pleasant even.
But I also feel nauseous consuming caffeine when fasting. I've come to suspect a major reason people eat breakfast is so their morning caffeine dose doesn't make them sick, though they may not acknowledge it.
Caffeine stimulates acid production in the stomach which can possibly trigger gastritis. An antacid might help there in lieu of the buffering effect of the food you'd normally be eating.
Maybe I should try it more often. Definitely feels good.