How do you tell a story about two sisters through a one-person show?

This became the central struggle for siblings Naomi and Deborah Vogt—and the quandary opened an innovative approach to performance, becoming a larger metaphor for the way they relate.

The brutally honest BIG Sister finds Naomi, who is an actor, telling the tale of how she lost 75 pounds as an adult, using a script written from the perspective of her sister, who is a playwright. The collaboration, which debuted at the 2018 Vancouver Fringe Festival,went on to win the Cultchivating the Fringe award.

The pair broached the subject while meeting up on a trip to Portugal. “At first I found it frustrating to have someone else try to tell that story,” offers Naomi, patched in on a conference call from Vancouver while her sister is at home in London, U.K. “It was the real frustration of having a sister who has never been fat and missed the nuance. We have different kinds of filters. So we decided on this structure where Deborah was describing my experience and I had to interrupt with my own experience.”

“It’s a little scary, and in some ways amazing, to sit and watch,” Deborah offers. “It’s amazing that I can’t control what she’s going to say.

“At the first production at the Vancouver Fringe, I was very visible to her while she said all those words,” adds the writer, who sat wordlessly in the front row for that stint. “This production is more scary and I have less control, because I won’t be sitting there.”

Naomi goes on to reveal that her improvised interjections reflect the siblings’ lived experience, from the time they were small children. “I’m outgoing and Deborah is shy,” she says. “I always spoke on her behalf.”

From that, you get some sense of the candid, straightforward approach the hit play takes to its rather explosive subject matter. BIG Sister digs into all the uncomfortable realities of body shaming and how Naomi found herself treated when she was heavier versus when she lost weight.

“The direction we’ve taken is to be as honest as possible about the lived experience of being fat and then the privilege that comes afterward,” says Naomi. “So many doors have been opened for me since I’ve lost weight. And I wish that wasn’t true. And it’s like saying that out loud is an act of oppression towards fat people. A lot of people who are fat don’t want that message put out there. But that’s how screwed up this world is for fat people. And by exposing the continuing trauma that’s had on me, we’re trying to shed light on what’s wrong with how society is treating women.

“This isn’t the experience of all fat people, and we’re so grateful that there’s people who live in fat bodies and don’t have the complexes I do,” she adds.

As the show navigates that issue, you’ll find that it just as bluntly exposes the Vogt siblings’ sometimes prickly relationship, including their struggles over control.

“I feel like I haven’t seen too many relationships like this on-screen,” Deborah says, “the sort of cruel and loving way that sisters can treat each other. On TV you see sisters brushing each other’s hair and talking about boys. We talk in the play about that being the opposite of our relationship.”

Obviously that realistic portrayal is hitting a chord, though. “I’ve been surprised by some of the emotional reactions we have gotten,” says Deborah, who has been able to see the work staged in her new home country. “A few people in London said they’d been inspired to call up a sibling they hadn’t talked to in a while.”

BIG Sister is at the Vancity Culture Lab from Wednesday (February 19) to February 29.