One more thing before I leave. About "food" and "foods"

You might want to visit the collective nouns for their usages. Nothing fancy there. In my article specifically, "junk food" refers one specific food - pizza, can't be replaced by "foods". Otherwise, generally speaking, there is no difference in "junk food" and "junk foods". People use them interchangeably. If I use "foods", then I am emphasizing the variety of food.