It takes the body on average between 3 to 5 days for the digestive system to shut down completely. For me it's about 3 days and when Day 4 rolls around, I know I'm pretty much over the hump. For some people, it takes 5 days and some people never have that horrible starving feeling the first few days... everyone is vastly different.
But once the digestive system does shut down, the hunger disappears. This is not to say you will not feel that hollow feeling now and then or think you're physically hungry, because you will have those moments... cravings when you smell food, etc... expect it and it won't be so difficult to deal with it when it happens. I usually suck a spoon of raw honey or agave nectar or drink a hot lemon/cayenne pepper tea when I'm around foods... helps with the temptations and cravings.
Feelings of aches and discomfort are signs of detox and this will happen off and on throughout the fast, some days worse than others.
The absolute best thing to do when you feel hungry whether it's physical or psychological and when you're feeling poorly, is to drink more green juices... disguise the taste with lots of carrot/apple if you need to... but don't limit yourself on the juices. The more you drink, the slower the detox, the less you feel hungry, the more energy you'll have, the faster you'll heal... Juices, lots of juices, are the key to the juice fast.
Good luck on your endeavors. I wish you all the best,