What causes munchies and what you like to eat when you get them:

[Bob the Awesome]

Argh ><

There's a center in your brain with THC receptors, it's called the Hippocampus. It regulates various things, including hunger: Hence, when you smoke, you get the munchies sometimes.

I must say, PB+J's are the way to go for basic munchy food ^_^