What kind of food did t rex eat?

Anything he wanted. Nice fat sauropods, mostly grass-eaters.Brontosaurs, PlesiOSaurs.

Edit: Not really Brontosaurus in the Jurassic period and PlesiOSaurs lived in the Jurassic period and lived underwater. Tyrannosauruses diet consisted mostly of Triceratops and other large Herbivores of the Cretaceous as well as oddly enough other Tyrannosaurus Rex's.