Apple peels contain a substance that seems to cause lower incidences of some cancers in those who consume apples regularly. There have been studies in the Scandinavian countries. I think it might be the quercetin, but am not positive.
I'll see if I can Google something on those studies.
That would absolutely explain it (at least in my eyes). Perhaps the body “knows” it has cancer and creates those cravings? Either way, I found it odd at the time but things like that never leave you.