Hi Wobbley woo don't do it, go and have a 2 min walk if possible, if not get up and wash some pots or something, anything to take your mind off that apple for a minute or two. Than make yourself a hot drink this will take away the hunger (what usually works for me is the ironing... I never think of food when I am ironing lol)
Hang in there Wobbly Woo, it does get easier Just think you have got through the first day and that can be the worst day of all! Once you get passed Day 3 and into Ketosis you wont feel so hungry...well, not as much as you are just now!
Just keep looking on here for inspiration; it's what I do! The support is brill.
An apple- what sort of a craving is that?!?! LOL! Only kidding!
Seriously, as the others have suggested- get busy, drink a glass of water, do something with your hands, distract yourself- it's only a craving- your body doesn't need the apple- it's getting all it needs from your shakes. It will pass...we've all been there, hold tight, you'll soon be in ketosis and not want to eat!