Proper ladies poke at a meal, gentlemen eat a meal, and teenagers devour a meal like ravenous cowhands who haven't seen the inside of a bowl since Christmas, and here it is July. Devour means to eat greedily.
The meaning of devour has grown to include the consumption of things other than food. If sit down to start a book, and look up ten hours later having turned the last page, you have devoured that book. If your after school job is devouring all your free time, chances are your grades are going to drop.