yes, exactly, the problem is not whether those are more or less nutritious, the issue is the lack of variety. It seems that gut bacteria only improves if your diet is very diverse. But modern industrially produced food is made from just a small list of commodity ingredients. If you are curious about these topics, you could check out "The omnivore's dilemma", a book by Micheal Pollan, or the video documentary "Food Inc." that is also narrated by Pollan