The singer and fiancé Eric Johnson welcomed daughter Maxwell Drew on May 1, and Jessica has been trying to shed the extra pounds ever since.
She told USA Today, "I didn't realize [the weight] didn't all come off with the baby.”
So far Simpson has “lost weight every single week" by watching her portions, working with a personal trainer and walking 60 minutes each day.
"My boobs are way too big to run at this point. I'm just walking,” she admitted.
The “Fashion Star” judge won’t reveal her starting weight and says that Weight Watchers isn’t pushing her to meet a specific goal on the scale. The program recommends that women Jessica’s height, 5 foot 4 inches, weigh between 117 and 146. "They want me to be healthy," she said.
"I'm not a supermodel. My body is not bouncing back like a supermodel. I'm just your everyday woman who is trying to feel good and be healthy for her daughter, her fiancé and herself."