OK! Exclusive: How Britney Got Her Body Back!

While vacationing at Las Ventanas resort in Los Cabos, Mexico, in late July, Britney Spears was the epitome of the California girl as she walked out of the surf in a white bikini that highlighted her newly toned and tanned figure.

In an exclusive photoshoot in the new issue of OK!, the singer reveals how she successfully regained her lean physique and how she's committed to being a healthy role model to her two young boys.

"I'm the healthiest I've been all my life," Britney, 26, tells OK!. "My diet has a lot to do with my getting into shape. I have no sugar. I don't eat fruit or even fruit juice because of the sugar. I eat chicken and salmon and rice. I eat avocados. I'll have egg whites for breakfast and sometimes turkey burgers for lunch. I try to do just 1,200 calories a day. It may sound like it's not much, but it's actually a lot of food if you eat the right things."

Of course, Brit also hits the gym on a regular basis, doing "lots of cardio and weights" five days a week.

The singer's comittment to being healthy is applauded by trainers like Miami-based trainer and owner of SOMA Fitness & Performance, Adam Cronin. Cronin, who has not worked with the pop star, says Britney's routine of following a 1,200-calorie-a-day, high-protein meal plan is ideal for someone who wants to drop pounds in a safe, healthy way.

"If you follow a vigorous workout program — plus this eating program — it is possible to lose up to 12 pounds in 30 days, in a very healthy, non fad-like way," Adam tells OK!.

For the full interview with Britney and all the exclusive pics, pick up the new OK! — on newsstands everywhere Thursday!