What is the connection between trustworthiness and eating the whole apple (details)

It was in a list of (joke) Rules for Men from a certain “Men’s” magazine.

Normally, I get what’s funny and isn’t, even if it doesn’t make me, personally, laugh aloud.

However, this one stumped me – and perhaps one of you can enlighten me; Rule number one: never trust anyone who eats the whole apple, stem, pits and all.

I do. Does this make me less than trustworthy? I don’t get it.

:0

Bonus: add your own Rules for Men/Women if you will.