What on earth is expensive junk?

Someone said something to me today I am still trying to figure out what it means. 

He said something along the line of stop eating expensive junk. 

But what is expensive junk? 

I don’t eat much junk food and so Dorito’s is out of the picture and therefore what on earth is expensive junk?

Are all the expensive food—and food is very expensive these days!—I’ve been eating junk?

So pray tell me what is expensive junk so I can stop eating it. 

pearlie