Next month marks the 15th anniversary of the cult classic, which, for Seyfried, only brings back good memories of great food.
"Oh my god, I ate everything!" she joked while speaking with ET at the Good for a Laugh benefit at Largo at the Coronet in Los Angeles on Friday night. "It was the first movie that I had ever done, so I just ate everything."
"I had the best time," continued Seyfried, who admitted it was more than just superior snacks that made the movie set so memorable. "It started [filming] in September, when I had graduated high school, so it was 'college' for me, and I mean, I was the luckiest person in the world. And the food in Toronto, craft service is [great]."
Rachel McAdams, Lindsay Lohan, Lacey Chabert, Tina Fey and more starred with Seyfried in the 2004 film, which went on to be a huge box office success. Over a decade later, the movie still has a huge following; it was turned into a Broadway musical last year.
The cast has since gone their separate ways, with Seyfried now happily balancing her acting career with motherhood. She and her husband, Thomas Sadoski share a nearly 2-year-old daughter.
"There's nothing you can do to prepare [for the terrible twos]. You just have to learn how to talk to them and try to connect. I just need her to know she can feel safe to feel whatever she feels with me, so we don't lose that connection," Seyfried said. "That's what I'm doing right now, just staying present and staying connected."
The actress, who, with Sadoski, hosted Friday's event to benefit War Child USA and INARA, organizations for children whose lives have been devastated by war, is also focused on teaching her daughter about giving back as she grows up.
"We can't help how we're born and what we're born into, and we should all get the same chances, and we should all have the same hope, and we should all feel the same sense of safety," Seyfried expressed. "It's just sad that it's not consistent throughout the world."
"If we have something that we can give to somebody else, it is our job to do that, to give our services, to give compassion, if it's just advocating for the rights of somebody else. That's our job," she added. "It's the most wonderful thing to be able to do."