Food fads have come and gone ever since humans had food choices (which has been a tiny fraction of human history). I saw this: Why we fell for clean eating.
I don't know who "we" refers to, but it didn't include me.
It was not long ago when the experts thought that cereal was the right breakfast food. That was mostly marketing, but Mr. Kellogg and others thought it might helpfully reduce sexual desire and promote clean thinking compared to "overstimulating" eggs, sausages, and pie for breakfast. Now "we" know cereal is garbage nutrition.
FYI, my usual breakfast is two coffees before my workout, and a protein shake afterwards. I am not claiming that that is "right" but it keeps me trim and strong. If I did manual labor all day on the farm, I'd go for eggs, toast, sausage, bacon, kippers, home fries, grits, and pie. We fed our young growing kids on breakfasts like that. Pancakes or waffles and bacon on Sunday.They grew, and got smart enough.