What is Miranda Lambert's diet secret?

CMA Female Vocalist of the Year Miranda Lambert is causing buzz this morning. Partly for that big win Wednesday night, but also because she's showing off a slimmer figure.

"I've been working out, but this thing is heavy!" Lambert said backstage, reports People.com, as she also showed off her trophy.
And she explained her new figure, saying she is turning 30 on Sunday and she thought she was fine with that, "but I guess I'm not because I feel like everybody always says 'It goes downhill from there.' So I just thought, maybe if I get ahead of it a little I won't have to work so hard later in life.".