In this context, "kind of" means "almost" or "like" or "almost the same as". In this context, "just" is unnecessary and doesn't really mean anything in particular. The word "so" is being used to have a similar meaning to "very". The word "just" seems to have been added for extra emphasis. Examples: "I'm excited" (least emphasis) "I'm so excited" (more emphasis) "I'm just so excited" (even more emphasis).

I'm just a native English speaker. My take on this is: "kind of" is a way to make an analogy. Rock and roll took much of the world by storm in many ways and he's saying food is doing something similar but not the same. "Slightly" isn't what is meant here. It is recognising it is different (it's food not another type of music) but implying it is capturing the feeling of the "in crowd" and it is going to be (or is) big. "just so" provides emphasis on the word "excited" rather than a direct meaning of "very", but thinking of it as very is good enough. You should probably think of "just" and "so" together.