Sen. McCaskill used 'Karl Rove diet' to lose weight

"Karl Rove started going up on TV with ads against me, and it's a year and a half away, and I realized, you know, I'm in the fight of my life here. I better get some energy, I better get some focus because they're coming after me big time," McCaskill said on MSNBC's "Morning Joe" Thursday.

The Rove-linked conservative action group Crossroads GPS is targeting McCaskill and other Democrats considered vulnerable in the 2012 elections.

"So, let me ask you this: have you written Karl a thank you note?” MSNBC host Joe Scarborough asked. “Hey Karl Rove, if you're watching: the 'Karl Rove diet,' seriously, I'll buy it if I can lose 50 pounds."

"I'll tell you when he's going to get that thank you note — the first Wednesday of November next year," McCaskill said, referring to Election Day.

McCaskill lost 50 pounds this year and has documented her progress on Twitter.

The Missouri senator also talked about the seriousness of a healthy lifestyle. She told MSNBC that the onset of her mother's adult diabetes inspired her to exercise and change her eating habits.

"I realize how hard things are for her and I don't want that. I want to be active and fit for as long as I possibly can," McCaskill said.

She said she lost the weight by scheduling time for exercise and cutting out most bread, pasta and alcohol from her diet.

For more on the McCaskill interview, including her views on taxes and deficit reduction, click here.