Kelly Preston at 50: 'I Feel Like I'm 25!'
10/22/2012 AT 02:00 PM EDT
"I feel incredible. It floored me for a bit, but now I love it and I feel better than I have in years," the actress tells PEOPLE. "You are as old as you feel and I feel like I'm 25!"
It doesn't hurt that Preston, who lost 42 pounds over the first 14 months after giving birth to son Benjamin on Nov. 23, 2010, has shed an additional 7 lbs. in recent months. "I go up and down one or two pounds without worrying about it," she says. "I think I'd like to stay at this weight. I feel really healthy and I have tons of energy."
While Preston credits the Organic Liaison weight-loss program and nearly two years of breastfeeding – "We're in the middle of weaning right now," she says – for her rocking new figure, keeping pace with an energetic 23-month old also keeps her young.
"I'm running after a 2-year-old and keeping up completely!" she says. "Ben runs around and three, four, five times a day we go outside and find frogs, millipedes and lizards. It's always, 'Mama, get it! Mama, get it!' "
Ironically, one of Preston's favorite birthday gifts was a huge basket of homemade treats from her best buddy, Kirstie Alley, who created the Organic Liaison program and cleared her own hurdle last year when she lost 100 lbs.
"The way I lost the weight was through Kirstie's [program], and breastfeeding, and the way I gained another pound is because of her!" says Preston, laughing. "She sent me a box of unbelievably delicious sweets – Rice Krispie treats, homemade jams, coconut macaroons, you name it I plowed right though it!"
But it was the gifts from her family, including a painted picture frame and photo album from daughter Ella, 12, and a painting of "little dots and little lines" from Ben, that truly touched Preston.
"Last month, Johnny [husband John Travolta] flew all my girlfriends and their husbands and our family to Paris for four days for my birthday party and we just had the best time ever. Absolute perfection," says Preston, who took in Barbra Streisand’s Brooklyn concert with Travolta and Ella on her actual birthday last Saturday.
"I can’t even put into words the experience because she was so magnificent. She said happy birthday to me [from the stage]. It was the best concert I've ever been to in my life, just magic. It was truly an amazing birthday."