PHOENIX - Joking that all the caffeine was "making me mean," Gov. Jan Brewer has changed her beverage of choice.

Chat with her in her office? It was inevitable. There was a bottle of Coke Zero on her desk - even before she became governor in 2009.

Staffers always knew to find a supply when she was on the road. And the crew that flies her around the state in a Department of Public Safety plane made a special effort to be sure there were several bottles on board before any trip.

But no more.

"I'm drinking Arnold Palmer Zero," she said.

"It's a mixture of tea and lemonade," the governor explained, with no calories. "And the chemists tell me that stuff that's in there is pretty darned good."

More to the point is what it doesn't have - carbonation.

"You can set it around and you can put it back in the refrigerator and then you can drink it again," Brewer said. The governor said it was not unusual for her to start a bottle of Coke - she preferred those to the cans - and then leave them around.

"And, of course, it would go flat," the governor said. "And then it was horrible."

But there's also a medical issue.

Carbonated beverages contain phosphoric acid. And that can leach calcium from the bones.

"And it's bad for old ladies like me," Brewer quipped.

Still, the governor isn't going cold turkey on her Coke Zero.

"I have one now and then," she said.

"But nothing like I used to," Brewer continued. "And, I tell you, I sleep a lot better!"