[MMM]

I am sorry, I wasn't clear.

"I like Japanese and Chinese food"

和食と中華が好きです。

It sounds like you like Japanese and Chinese food exclusively.

和食や中華が好きです。

"I like things like Japanese and Chinsese food."

It sounds like you are into Japanese and Chinese food, but probably other Asian foods which are similar, too.

That's the difference.