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Teen Mom 2's Kailyn Lowry popped out her adorable son, Lincoln Marshall Marroquin, on November 16, and she's been on a mission to get healthy ever since! This gal is a champion of beauty being "sizeless," but she definitely wants to shed those pesky post-baby pounds through a combination of diet and exercise, and guys? She's already off to a great start!

“Kailyn has dropped about 15 pounds already,” a source tells RadarOnline.com. “She’s saying that doctors told her she lost 12 pounds just giving birth.”

Kailyn plans to hit the gym as soon as she gets clearance from her doctor, and the source says that she expects to get a green light by the end of December. Apparently, she'll be "in the gym every day trying to lose the rest and training for the race she’s doing in April,” and hopes to reach a goal weight of 150 — which is pretty slim considering how tall she is!

Kailyn has a ways to go, but her placenta pills are helping her keep up with Isaac and Linc, and the source tells Radar that "compared to when she had Isaac, she definitely has way more energy. Whether it’s the pills or not, she is giving credit to the pills."

Are you surprised that Kailyn has lost so much weight so quickly? Don't forget that she's also breastfeeding, which bruns hundreds of calories a day!

Source: RadarOnline.com