I fasted for roughly 72 hours giver or take. Nothing but water. But the fasting only concluded what I already had guessed- that food and acne have a minimal correlation. My acne did not improve per se within those 72 hours or the days to follow. The days following I ate very little, only green veggies and such. If my acne had been caused from say caffeine, chocolate, sodas, bad dieting, ect... I feel I should have noticed at least some relief. I believe very strongly that acne is more hormonal\stress related then anything else. Perhaps if I had fasted longer I would have finally started noticing improvements. I know studys have shown that fasting does help acne, but these tests generally involved much longer fasts (10+ days). Just thought I'd share.
Why would you purposely fast for that long?
That is a lot of time to go without any kind of nutrient in take.
I'm not sold on the fasting thing as i believe a lot more research is needed albeit a lot of interesting data is coming out of it.
However, as already stated i would suggest getting your daily in take in to 5 hour window.