02/27/2008 at 11:00 AM EST
Her new daughter, Harlow Winter Kate, in her arms and her boyfriend, Joel Madden, by her side, Nicole Richie tells PEOPLE for its new cover story – on newsstands Friday – that when it comes to the changes she's experienced in the six weeks since the baby's arrival, "It's almost like I don't even remember what life was like before her. She gives life a whole new meaning and a whole new purpose."
As for breastfeeding, "There's just so much I can't eat because she's sensitive," says the new mom, 26. "I eat really bland [food] – chicken noodle soup, vegetables, fish. I had to cut out milk, no tomatoes, no lettuce. You think you have to cut everything out when you're pregnant, but you really have to cut everything out when you're breastfeeding."
And while Richie says, "I don't know" how long she was in labor, "because I don't know what time I actually went into labor, but I pushed for 10 minutes," Madden, 28, said of his daughter: "She came out and she was crying. The doctor goes, 'Well, it looks like you got a little girl!' "
For more, including who was the first to cry – Nicole or Joe – who the baby looks like and for whom she was named, pick up this week's PEOPLE, on newsstands Friday