I think you have been subjected to (classical) conditioning. These fast foods that you've mentioned is desirable to you. And you associate those words to the presence of the fast food. Therefore when you hear these words (stimulus) you'll have a response to it. This experiment was first carried out by Ivan Pavlov.

He did a test on some dog by ringing a metronome before feeding them and observing whether they salivate. At first the dogs only salivate after seeing or smelling the food. He continued doing the same thing for a few days. After a few days, the dogs started salivating once they hear the metronome, even without having the food.

More facts can be found in Wikipedia: Classical Conditioning