Debra Messing recently stopped by ABC News to share some of the secrets behind her 20-pound weight loss. The 45-year-old actress says she made a "very, very big change" in the way she approaches nutrition "about two to three years ago." Her original motivation for the different approach was to increase energy, not to lose weight. "I think it made a big difference in how I look or at least how I'm perceived to look," Messing says. "I lost like 20 pounds, it wasn't my intention ... I made the change because I was just tired all the time. For a long time, I just accepted that was the plight of a working, single mother." "I grew up on fast food and candy every day," the actress recalls. "Pizza and french fries and burgers -- I love food and I've always loved food. Vegetables were not a part of my life at all." Nowadays, Messing starts her morning with a green juice of kale, spinach, celery, ginger, lemon and cucumber, and eats "really, really clean healthy foods." "[Nutrition] shows on the outside in your hair and skin and even the clarity of your eyes," she asserts. "[Green juice] really gave me more energy. That made an obvious difference for me, in me feeling strong." Messing recently appeared alongside Leighton Meester and Billie Joe Armstrong in the upcoming movie, Like Sunday, Like Rain. The actress also stars in the pilot for potential television series, The Mysteries of Laura.