"I'm definitely in better shape than I was last time, definitely. I'm just more active and I cut all the crap out of my diet! It's that simple."
Bristol is paired up again with her partner from season 10 Mark Ballas and the two scored
19 points out of 30 for their cha cha. Judge Carrie Anne Inaba declared the 21-year-old is the "most improved" returning celeb contestant.
Former vice presidential candidate Sarah Palin and father, Todd, accompanied her son Tripp, 3, in the audience to cheer on Bristol.
"My kid's a lot more rowdy, a lot more active, the single mom said. "I'm running after him a lot! He's huge! He thinks he's a teenager already."
Her family's support in the dance competition is encouraging for Bristol and she said, "If I ever hear anything bad that's being said about me or my family, it just gives me motivation to do better, and that's what I do."
Meanwhile, her partner is happy to have Bristol back on the dance floor with him.
"We picked up where we left off. We stayed in touch since last time and we just went back into it. We balance each other," he explained. "I'm loud and obnoxious and she's quiet and chill."