Yothers before (left) and after
JEN LOWERY/STARTRAKS; MANDO GONZALEZ
Even after losing 42 lbs., dropping five dress sizes and winning the fourth season of VH1's Celebrity Fit Club, Tina Yothers still didn’t realize how much her body had changed – until she tried to toast her victory at one of her favorite L.A. eateries, In-N-Out Burger.
At the drive-through, Yothers ordered her usual, a double-double burger, but couldn't finish it. "I took, like, three bites – that’s all I could do!” she tells PEOPLE.
Besides cutting back on portions (she follows the NutriSystem plan), Yothers, 33, continues to work out three times a week with her trainer, doing lots of cardio (jumping rope is a favorite) as well as lunges and squats, and is down to a size 8.
"We call each other from our workout sessions and we're huffing and puffing," says fellow Fit Club-er Carnie Wilson, who became good friends with the actress during the show.
Yothers – who a year ago hit 210 lbs. while pregnant with daughter Lillian Grace – now celebrates by showing off. "We've gone to the river three times this year," she says, "and I’ve worn a bikini every time!"