Mary Tedesco began her fitness career 15 years ago in Manhattan Beach, California. At the time, she was overweight and not very athletic. Then she met her husband, Michael, a triathlete who introduced her to weight training. He would wake her early in the morning to work out -- and she's never looked back. 

"I was just amazed at the way my body changed with weight training and long bike rides along the beach," she says. "On the outside, physically, I looked so much better, but also on the inside I felt like an entirely different person. So much happier and relaxed. So much more confident and self assured. I felt empowered."

So Tedesco decided to help empower others. She is now the owner of Body Fit Personal Training in Cross River, New York, and is Martha Stewart's personal trainer. She's an AFAA certified personal trainer and an NASM candidate with additional certifications in yoga and pilates. She has appeared on "The Martha Stewart Show" and is on Body+Soul's editorial advisory board.