AFTER WOWING EPIC Records chairman/CEO L.A. Reid, Meghan Trainor is winning over fans with her debut hit, “All About That Bass.” The song, which mixes a self-empowerment message with a hooky doo-wop beat, bounds 8-4 on the Billboard Hot 100 and crowns Digital Songs, where it lifts 2-1. “L.A. said, ‘No one has written anything like this yet, so I can’t compare it to anything,’ ” recalls the 20-year-old, who has penned songs for acts like Rascal Flatts. “Usually, I’m writing for other faces. But now it’s mine, so I can say whatever I want. That’s so cool.”
Trainor, a Nantucket, Mass., native who now lives in Nashville, tops Digital Songs with a 17 percent jump to 197,000 sold in the week ending Aug. 10, according to Nielsen SoundScan —…