The 33-year-old actress gave birth to her first child daughter Lincoln with actor partner Dax Shepard in March 2013, reported E! News.
"I'm definitely trying to lose it - I want to be clear. But I'm not letting it keep me up at night and I am not letting it become the narrative of my life for the next year," Bell said.
"It's like, by the way, don't you want to look like you've had a baby?," she added.
The actress is exercising and running to lose the weight.