My 3 year old likes to eat whole apples. But she tends to eat straight through them, disregarding the fact that they have an axis of sorts. She gets to the core, and she's done with it, even though there's the other half of the apple to go. It's too messy at that point to turn it over and try to hold it and eat the other side.
She also doesn't want to listen to me explain that the ends of the core are indented and not to start there. Consequently it's even harder to hold it, since she's bitten off where I'm trying to get her to put her thumb. Besides, her hand is much too small to hold the larger apples I tend to buy.
So we put corn holders into the ends of the core, and she ate all around that big thing several times. Worked like a charm, and she thought it was great fun pretending her apple was corn on the cob.