Luna appeared on KBS 2TV's 'Hello' on June 13, where she was asked how she got even prettier with the release of her solo album.
She surprised everybody by replying, "I personally gained about 3 kg (~ 7 lbs) and made a comeback." Regarding why she gained weight when most people try to lose it, Luna said, "I did it so that my song filled with high notes could come off stronger."
Many other female artists, like Ailee and Solji, had said before that they needed more weigh to hit high notes or just sound better. Nice dedication to your art, Luna!