He told Sky Sports News: "I've cut down (on alcohol)... not that I was ever struggling to cut down!
"I just decided a glass of wine here and there, no nights out before I go on tour, just trying to be really, really strict on my diet to get into the best possible physical shape, keeping rugby fitness up, keeping strength and power up as much as possible because we're going to need it in New Zealand."
The Ireland centre also reiterated his desire to approach the job of Lions skipper in his own way, rather than mould himself on previous leaders such as Martin Johnson.
"It's difficult to follow a lead, I'm not going to do it his (Johnson's) way or any other captain's, like Keith Wood," O'Driscoll added. "I'll do it may way."
"I don't want to try and copycat, you've got to be natural, be your own captain."