Mostly food, but some non food, too. Usually when they're young. Like socks, remotes, etc. But definitely food. Each dog has his/her preferences. Frank is more fond of apples and pears than steaks, for example. Charlie (Newf house guest) turns up her nose at dog food, but will eat piles of sticks and chew the crotch out of your favorite shorts that you like to garden in. Brym (mini American Shepard house guest) is fond of hoovering the floor, but slightly suspicious of things you offer by hand. But I would not say any of them is too picky. If you offer, they will certainly show some interest. I know this doesn't answer your question, but there aren't many Newfs that will turn down stuff.