Because loving is stronger than liking and one does not simply "like" italian food... it is just too good. ;) But to answer your question, "I like italian food" would be "mi piace il cibo italiano". It is a different verb ("piacere") with a different meaning. "Amare" strictly means "to love", consequently, "amo il cibo italiano" strictly means I love italian food. I am not sure if you already learned "piacere", but don't worry, it will come up here. ;)
OK. This may sound goofy to some; but, I love dogs. They are truly wonderful and amazing creatures. (many cats too). I have frequently stayed in Sicily to "nanny" my friend's adored Pug. I never quite understood the peculiar looks I received when I would say "Amo i cani"!!! But guess what? I do love them!