Credit: Davis Factor/Icon International

The secret's out on how Kim Kardasian stays slim while maintaining her famous curves.

"Changing my eating habits makes a big difference," the E! star tells Us Weekly of keeping her size-2 bod trim. "I wake up and eat eggs with turkey bacon, then salad for lunch (Greek salad with no olives is her fave) and fish, pasta or chicken for dinner."

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The onetime sweets lover, who recently dropped refined sugar from her diet, has also been inspired by big sister Kourtney, 32. "She's taught me to eat more organically," admits Kardashian, who has also downed wheatgrass shots with her sis. "She's a bit extreme, but slowly I'm learning to love it."

As for her workout routine, the newly single 5-foot-2 star sweats it out -- hard! There are no water breaks during the 31-year-old's hour-long sessions with Gunnar Peterson. "Every minute is accounted for," says the trainer. "You go from running to pull-ups to lunges and crunches to overhead presses. You get more work done in the same time."

So how does Kardashian keep her curves while lowering body fat? "We emphasize glutes, abs, legs and shoulders," says pro Peterson. "And the big movements we do keep her metabolism revved after our sessions."