Toast can also be a synonym for 'done'. Not just along the lines of bread or even food in general, but for people as well. For instance, jocks have often been heard informing the opposite team that they are 'toast' before a big game.
Possibly the best example of this usage is in the classic original Ghostbusters, in which Venkman (Bill Murray) determinedly exclaims "This chick is Toast!!!!" after being zapped with lightning (a-la 80's special effects) by a hell woman with spiked hair (a-la 80's style).