"My food obsession was out of control," the Morning Joe host tells PEOPLE of her eating disorder

Mika Brzezinski’s secret is out: She’s struggled with food addiction for over 30 years.

“I had honestly been lying to myself about how serious my situation was for years, but I was way too embarrassed to bring it to the forefront,” the Morning Joe host, 46, tells PEOPLE. “I feel like it’s my one big secret.”

Now, she’s sharing her experience in the new book Obsessed: America’s Food Addiction – And My Own.

“I’m supposed to look like I have it all together,” says Brzezinski. “And it’s supposed to look easy. Admitting that is hard because you feel like you’re taking a veil off.”

From the time she was 15 to her early twenties, Brzezinski says her appetite was out of control.

“I was eating large Dominos pizzas in one sitting – voraciously and still wanting more,” she says. “I thought about my weight all the time.”

Her college years were particularly painfuI. “I couldn’t concentrate on anything,” she says. “I remember staring at a book, trying to read a paragraph over and over again because I was so hungry and disgusted with myself. You know how you salivate when you smell fries? It was that kind of hunger. All the time.”

Once she became an on-air reporter, the obsession was fueled further.

“I don’t know if you’ve noticed,” she says, “but a lot of the girls on television are pretty thin. The pressure to be thin is humungous.”

Brzezinski decided to be honest about her food addiction, in part, to help her two teenage daughters – Emilie, 17, and Carlie, 14. “They deserve my honesty,” she says.

As a result of coming forward, she’s loosened up with food – a bit – and now weighs more than she has in years.

“I even eat bread at lunch,” she says. “And I eat chocolate. I tell myself, ‘It’s okay to be 132 lbs., Mika.’ ”

But rest assured, she’s not giving up her signature body-con shifts – although these days she’s more apt to wear a cardigan.

“If I am really feeling awesome, I go sleeveless,” she says with a laugh. “But I lift weights and I think my arms look pretty good!”

For more from Mika, pick up the latest issue of PEOPLE, on newsstands Friday.