Jennie Garth’s slimming down secret is not what you might think. “I eat a lot now,” the Dancing with the Stars contestant says. “I love a late-night Dorito.”

The 35-year-old mom of three (Luca, 10, Lola, 4, and Fiona, 1) has found the alternative to dieting: “Rehearsing for six hours.”

Garth says, “When I decided to do [Dancing with the Stars], I did pilates three days a week and cardio twice. I hated it, but it helped. Once I started dancing, things changed faster than when I was just working out.”

Garth says she’s dropped 10 pounds since starting on the show, “but it’s more about the inches and toning. My jeans were a 29 when I started, and I’m wearing a 27 now,” she explains. “It’s great to be able to go to the back of my closet and get the clothes I wore [prebaby].”

Actor husband Peter Facinelli, 33, is enjoying the benefits of Garth’s dancing as well. “He said, ‘It’s like I got a new car!’” she tells Us. “He can’t keep his hands off me. To the point that it’s like, enough!”

Uh-oh. Garth may be dancing her way to the couple’s fourth baby!