The 10th runner-up for 'American Idol' is looking svelte!  Following in the footsteps of former Idol's Jennifer Hudson and Carrie Underwood, Lauren dropped a whopping 25 pounds!  See how she did it!

She looked good while she was on Idol, but she looks fantastic now!

How did she do it?

"Changing my diet was the big thing," the 5-foot-7 Georgia native tells the new issue of Us Weekly (out now). "I had to learn correct portion control."

"I eat an egg-white omelet for breakfast, shrimp and veggies for lunch and chicken with asparagus for dinner," the single 16-year-old high school junior says.

Whatever she's doing, it's working!  Lauren Alaina looks great!