Jessica Simpson is getting ready to show off her post-baby body in new commercials for the weight loss-program set to run next week, but first she’s talking about how she shed the pregnancy pounds.

“I let myself indulge in everything I wanted because it was the first time I was ever pregnant, and I wanted to enjoy it,” Simpson told USA Today. “I wanted to be happy and eat what I wanted.”

She explained that while she was pregnant with her first daughter, Maxwell Drew, she had a “big appetite,” which she filled with macaroni and cheese.

“I didn’t realize [the weight] didn’t all come off with the baby,” she says.

After giving birth in May, the new mom changed her eating habits with help from Weight Watchers. Though she has said she’s never felt any pressure to drop the pounds, she says she’s “lost weight every week” by sticking with the PointsPlus program, which assigns points to foods based on the amount of protein, fiber, carbohydrates and fat in them.

But Simpson does make sure she treats herself sometimes.

“I’m a woman who wants her chocolate,” she said. “I allot myself a fun-size (bag) M&Ms. I eat one of those, and my craving is satisfied. I don’t need the whole bag of M&Ms.”

Simpson’s also started exercising, along with using a pedometer to track her steps on walks with her fiancé, Eric Johnson, and her little girl. Though it hasn’t always been easy, she has kept a positive attitude throughout it all and hopes to be a role model for other women.

“I’m not a supermodel. My body is not bouncing back like a supermodel,” she said. “I’m just your everyday woman who is trying to feel good and be healthy for her daughter, her fiancé and herself.”

- Shannon Carlin, CBS Local