A fork of Rural Dictionary
When an Awesome friend starts dating a girl and changes himself so much that he is no longer himself, Thus becoming the Diet Coke version of himself.
Clint: Adam we should invite Nate out to the bars with us!! Adam: I dunno...He's going to invite his girlfriend and when she's around he's like the Diet Coke of Nate!! Clint: Oh what a Diet Bro!
diet dude bro refers to someone who is very funny
have you seen dylan's new video? He acts like a diet dude bro