The singer wasn't always 'All About That Bass'

Credit: Kevin Mazur/Getty

She may be “All About That Bass” now, but Meghan Trainor used to struggle with her body image.

The singer, who just took home a Grammy for best new artist, tells CBS Sunday Morning that she used to hide behind bulky clothing.

“I – every day – wore sweatshirts and sweatpants to cover up my body because I was so insecure,” Trainor, 22, says on Sunday’s episode. “And it would be summer. And I would go on vacation and I’d be in Trinidad and Tobago, 90-degree weather, and I’d be wearing sweatshirts.”

Her biggest concern wasn’t her ‘bass,’ but her arms, Trainor says.

“I didn’t want to show my arms,” she says. “I didn’t want to show anything, and I was just so insecure and uncomfortable, and I thought, like, ‘All right, if I’m fully covered – I’m good. And that’s not what I should have been feeling.’ ”

Trainor previously told PEOPLE that her hit song finally boosted her self-esteem.

“Confidence was always something I wanted in my life,” she said. “But I was always very insecure growing up. When I wrote ‘All About That Bass,’ I wrote it wishing I was that confident. Then one day, they told me I would be the one singing it. It helped me to believe what I was singing.”

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And the way that fans have fully embraced her – size and all – helped Trainor finally move past her body image issues. Now she’s proud to be a role model for them.

“I get messages all the time, ‘I hated myself, I didn’t want to go to school. I was so uncomfortable, and now I love myself. And I was in a really dark place until your song came out,'” Trainor tells CBS. “And I was like, ‘Whoa, man, we’ve got to do more of these. We’ve got to do more of these songs.”