The best diet is the one you'll stick with. If you want to get into fiction but haven't read a lot before, try finding a short story collection. "Best short stories of 2026" or something more genre if you know you like a particular genre. I like Weird Fiction and cosmic horror for example, so I might look for a Weird Fiction reader. If you don't like a story, you can move onto the next one. Once you find a writer you like, try reading their longer form stuff.

Same thing with nonfiction. Browse through publications in subjects you know you're interested in. If you want to learn about String Theory or ancient Rome or modern Japan, pick up something focused on that and move outward.