Ashley Greene blue bikini July/August 2010 Women's Health

Ashley Greene shows off her amazing abs on the July/August cover of Women's Health. Photo courtesy of Women's Health

Unlike the vampire she portrays in the "Twilight" films, Ashley Greene doesn't deny herself when it comes to her diet.

"I'm a big believer in feeding your body what it needs," Greene, who plays bloodsucker Alice Cullen, tells the July/August issue of Women's Health. "Deny yourself something and you're going to end up shoving your face full of it."

That's why the 23-year-old actress, who recently signed on as the new face of Avon's Mark cosmetics, doesn't obsess over her weight and refuses to slim down to scary-skinny proportions.

"A lot of people like to be supertiny," she explains, "but I don't want a child's body -- I want a woman's body that is extremely fit. It's so much sexier."

Greene shows what she means in "The Twilight Saga: Eclipse," which arrives in theaters June 30. The action-packed film required the 5-foot-5 star to get into fighting form with a regime that included cardio, squats, and planks.

She even challenged her cast mates to squat contests. "I'm a competitive little sucker," Greene laughs.

When it comes to fashion, however, Greene takes a more laid-back approach. "On the red carpet, it's complete glam. But at home I'm a jeans and T-shirt kind of girl," she tells the magazine, which hits newsstands June 29. "Simple can be beautiful."

In related news, read what Kristen Stewart told Elle about her red-carpet attitude.