The Walking Dead star's classmates poked fun at her thin frame and nicknamed her "snap".
"I was very skinny," she tells Health magazine. "You know when your knees don't even look like they're attached to your body? Kids at school called me 'Snap', like my legs were about to snap because they were so thin."
"I was so gangly, even sneakers looked awkward," she continues. "Everybody kind of goes through some phase, and it's hard if you're singled out for anything. But there was this one boy in particular who made fun of me and, it's funny, then later, when we were 18 or 19, he wanted to go out with me."
Lauren admits she continues to struggle with her body image while working in Hollywood, but she chooses to focus on what makes her feel good.
"I've definitely learned to let go of some of that," she says. "One thing I always think about is, at the end of the day, nobody really cares about you as much as they do about themselves. It's a very reassuring thing, in a good way. Pay attention to yourself, and use that energy and put it towards yourself."
And she has a lot of things to be grateful for as America's Thanksgiving holiday looms: "Somebody said to me the other day, 'If this moment isn't the best moment of your life, you're doing something wrong'," she adds. "And I think about that all the time. Because me not liking where I'm at is such a waste of energy. And being able to be there for others is only coming from self-acceptance. You have to do what makes you feel good, but for me it has to come from that spiritual side first."