Flavors include Naked Berrylicious, Glorious Greens, and Tropical Sunrise (suggested retail price of $3.99)—all made with real fruit and blend of natural, upcycled citrus fibers with 9 grams of fiber.

I constantly try to take a couple of bites of fruit.” She’ll now mix Naked drinks into her during-match energy repertoire. “I’m excited to add that on court,” she says about the juice ...