Fun. lead singer Nate Ruess says the band's successful year has taught him "that I need to take better care of myself."
The trio, which includes guitarist Jack Antonoff and keyboardist Andrew Dost, has been on a wild ride since its dark pop-rock sophomore album, Some Nights, was released last February.
The group's second single and title track is a multiplatinum radio smash, and their album is near platinum status with 958,675 units sold, according to Nielsen SoundScan.
But Nate, 30, said: "(The year) really put us through the ringer as far as everything is concerned, and we didn't get a lot of sleep, so it was pretty rough.
"But what was cool is that I quit smoking and I cut back on drinking and I just made sleep a priority - and I think that's what all of us did."