It goes back and forth. Fiber was also big in the 1990s, and protein big maybe like 2004-2016 because of the Atkins diet trend that ended when it turns out that's not a great thing to do long term, and doesn't prevent you blocking your arteries with cholesterol.

We've literally had this trend before, recently.

Genuinely, fiber is always important. It's something we actually don't get enough of on average. Forget the trends and influencers, just make sure you're eating plenty of fiber.