>>862783Not eating for three days once will not have any effect on your health whatsoever.
Drink your fluids and enjoy the experience. And remember, drinking sugary water is cheating.
The hard part is when your glucose reserves are used up (about 300 to 500 grams). You body will give you heavy bouts of hunger when it is forced to turn fat into energy. Don't even think about going to work without eating, it will not end well, you will end up light headed and make mistakes.
Also, no shame in giving up really. Humans have a brain that costs a lost of energy, but we are clever enough to feed that brain constantly.