It's not a generally known fact, but gnawing on a plank of wood can stave off starvation for almost a day, in the same way that shoe leather can. The act of chewing and mastication fools the brain into thinking its receiving nourishment.
As a survival tip, it's not a very popular one, although it does see a lot of use among lumberjacks when they run out of lacy underwear to devour.