Katharine McPhee said the "biggest challenge" of being pregnant was dealing with resurfaced feelings tied to her previous struggle with an eating disorder.
"I definitely want to be candid about my journey," McPhee, 36, said on an episode of Dr. Berlin's Informed Pregnancy Podcast that recorded while she was pregnant and was released on Monday. (McPhee and her husband, producer and composer David Foster, 71, welcomed a son last month.)
The "American Idol" alum said the first trimester was the most difficult as she dealt with her changing body and feelings of fullness. McPhee said eating one salad while pregnant instead felt like she had eaten three.
"I was so stuffed. It was really a transition and balance for me to figure out the food stuff," she said.
McPhee has been candid about her past struggles with bulimia. The "Smash" actor said she struggled with an eating disorder off and on for many years, but finally got help right before she went on "American Idol."
"It's something that I think if you have issues with food it's always something that there are phases when it comes back into your life and it haunts you and then you get a hold of it again," McPhee said.
While the new mom said she has "felt really stable in my life in the last four or five years, and my weight has been more consistent," the old, familiar feelings creeped back in a way she didn't expect.
"Feeling like there was a relapse after getting pregnant was really shocking and upsetting and concerning for me, because I was suddenly so obsessed with food, starting from this first trimester, and I had such a distortion of the way that I looked," she said.
McPhee said she spoke with a psychiatrist who helped her before "American Idol" and learned that the way she was feeling is common for women who have previously struggled with eating disorders.
"And it made me feel so much better that I wasn't alone in that headspace ... by just meeting with him and him talking me through it," she said. "It wasn't like he gave me a bottle of pills and said, 'Here's your pills for anxiety.' That's not what he did when he met with me, but he was just talking through it and asking questions."
A representative for McPhee confirmed on February 24th the birth of her first child. McPhee hasn't yet shared a name. This is the first son for her husband, who has five daughters from past relationships.
McPhee can be seen next in the upcoming Netflix series "Country Comfort."