Jennie Garth is proud of her slimmer shape!

During her cover shoot for the January/February cover of Health, the 40-year-old actress explained how she lost 30 pounds midway through 2012 -- and also revealed how she's been able to keep the weight off.

"I've been working out really hard. I've been weight training with a trainer three days a week. We do boxing, kickboxing -- lots of weight lifting and training and jumping all around like crazy people," the mother of three laughed. "I really never sit down! I think that's basically the secret -- not sitting around."

Though fitness is a priority for the Beverly Hills, 90210 star, maintaining a balanced diet is equally important. "One of my favorite healthy things to eat is salad with beets on it. I love beets. I can't get enough beets lately," the 5-foot-5 actress said. "I like to eat them or drink them."

To see more behind the scenes moments from Garth's Health photo shoot, watch the video above now!