Originally Posted by
BiziBB
As long as the core isn't too bitter (and I'm not in an inappropriate setting) I like to eat the entire apple, core and all.
I figure the roughage can only help in the fight against bowel cancer.
Of course half of my apple intake would be through platters or buffets so the above naughtiness doesn't apply most of the time.

Don't forget to spit out the pips as they have cyanide! Which is at least partly responsible for the bitter taste.
It won't kill you or even make you ill in the quantities you're likely to eat, but I'd imagine eating the pips would cancel out or temper some of an apple's other health benefits.