With his smart, bracing comedy Brittany Runs a Marathon, writer-director Paul Downs Colaizzo breathes new life into the old mantra "It's the journey, not the destination." The film, his feature-length debut, follows its endearing titular character down the long road to self-actualization, chronicling all her stumbles and awkward detours along the way with a deft mix of humor and heart.

Brittany (Jillian Bell) is a wisecracking 27-year-old New Yorker with a dead-end job and a penchant for stiff drinks and late nights out. When she goes to the doctor to secure a prescription for Adderall, he instead suggests she shed 55 pounds, or, as she puts it, "the weight of a Siberian husky." She's too broke to join a fancy gym, but her well-intentioned neighbor Catherine (Michaela Watkins) has a solution: Why not start running with her and her club? After a little nudging, Brittany straps on her Converses and manages to make it a block, then two, before she's huffing it around the city with Catherine and her new gay friend Seth (Micah Stock), a similarly inexperienced runner who keeps her company as she finds herself frequently bringing up the rear. Soon, her goal becomes clear: She will not only participate in the New York City Marathon, but also set her aimless life on course.

Colaizzo, who up to this point has mostly worked in theater (his 2013 Off-Broadway play Really Really starred Zosia Mamet), based his screenplay on his best friend Brittany's own experiences in her late 20s, when the two were roommates. She, too, decided to run the marathon as a means of shaking herself into action, a decision that reminded Colaizzo, who grew up in a conservative Georgia town, of his own choice to finally leave the closet after college. For him, Brittany Runs a Marathon—which took home the U.S. Audience Award at this year’s Sundance Film Festival—is as much the story of his coming out as it is a love letter to his BFF.

Colaizzo recently spoke to NewNowNext about body positivity, avoiding cinematic clichés, and why there's a little Brittany in all of us.

When did you know you had to write this?

I was a living with my friend Brittany. We’d gone to college together and fell out of touch, but I needed a place to live and she needed a roommate, so I moved in with her. We very quickly started having conversations about life and happiness and fulfillment and what that meant to each of us and if it was possible and how we could get it. After that, she went for her first run, and I thought, This is a movie. So I started outlining it. I told her about it a few months later. I said, “I don’t know if I should tell you this, but I’m writing this movie…”

So you were secretly writing it?

Yeah. I was like, “It’s kind of about you.” She said, “What’s it called?” I said, “Brittany Runs a Marathon.” She said, “How fast does she run it?” I was like, “I’m not sure she’s gonna run it. She might not. She gets injured. Because it’s about distance traveled, not about actually finishing a marathon. So I don’t know…” And two months later, Brittany got injured and couldn’t run her marathon in real life [laughs]. She was mad at me.

You were basically painting her destiny.

I know! Sorry! I wanted to have a movie that was fun and funny and about an archetype like Brittany but not make her the butt of the joke. I wanted to make her the everyman, make her the hero, make us relate to her while we were still laughing and learning about ourselves.

So she ultimately let you, uh, run with it.

Yeah, she was great. I was 25, 26, and it was a pipe dream. You don’t think these things will ever get made. We had no connection to the movie business. I was only working in theater. More and more we were like, “Cool, hope it happens.”

Jillian Bell as Brittany in Brittany Runs a Marathon.

The idea almost feels ahead of its time. We were writing it before the whole body positivity movement.

Yeah, isn’t it weird? It was 2011. That was always a thing, but it wasn’t having the moment it is now. And this film had the potential to be filled with landmines, especially telling it as a man, but the intention was always to make something out of a place of love and empathy. There were very few instances of course correction, because I was vigilant to make sure I wasn’t doing anything insensitive and disrespectful.

You mentioned landmines. The body positivity movement is tricky territory: We’re asked to accept people for their differences and limitations, but there are also health issues related to being overweight or obese. How did you navigate that?

I wanted to make sure that any point of view on weight or weight loss or body image came from the point of view of the lead character. I’m personally not that interested in a message about health and fitness. I’m interested in self-efficacy and self-agency and self-respect and dignity. By putting all that through the lens of the character’s journey, we’re telling a story about one woman and her relationship to her body and her future and her life. It’s not about my relationship to her.

Brittany takes a fascinating journey. There are moments when you’re rooting for her, but then there are moments when she’s actually sort of despicable.

The idea is that she’s three-dimensional and flawed.

In one scene, after she's gotten thinner, she sees an overweight woman arrive at a party and is confronted with her past and potential future. I think it’ll be a difficult, uncomfortable, and maybe even controversial scene for some viewers. Why did you choose to write it?

This is a story about a woman against herself. She’s the protagonist and the antagonist. The idea was, “How do we dramatize her rock bottom?” The best way to do that was for her to project her fears and insecurities onto another person. The reason she projects them onto this woman is because (a) she’s judging her and (b) this woman dares to be happy. And she can’t fathom that this woman would be happy. That’s the real crime here, and I think we’re all guilty of that. People post things on social media, and they seem ridiculous to us and blissfully unaware, and that’s what gets us more than anything. We’re like, “How can they feel good about themselves doing that and looking that way?” Well, that’s our insecurity. I wanted to explore her taking out her insecurity on somebody who was a projection of herself.

On the flipside, a film like this has the potential to fall into treacly, clichéd territory. Yet it has to be sweeping in some way—I mean, consider the title alone. How did you strike that balance?

Character. That’s where my playwriting background comes in handy. I’m interested in psychology and what people are feeling and why they’re doing what they’re doing. We’re telling a story about people changing their behaviors and attitude, so every action has to be justified. You look at the title and you’re like, “There’s gotta be irony in that.” Then you start the movie the same way: with a woman we laugh at whom we’ve been taught to laugh at, who’s so ridiculous that we feel comfortable laughing but never even consider empathizing. After the first 10 minutes of the film, we start shifting that tone, allowing the audience to keep their laughter but also asking them to examine this woman and empathize with her. The idea is to maintain a balance between sympathy and empathy throughout so that when you get to the end—spoiler: She runs a marathon!—the title takes on a new meaning. It’s a metaphorical marathon. We do with the title what we do with the character: It’s much deeper than you anticipated.

Brittany Runs a Marathon director Paul Downs Colaizzo.

You’ve been a playwright up to this point—this is your first film. Was it a leap?

Yes, but it was about getting as prepared as possible and translating things I didn’t understand about film and cinematic techniques and technical aspects into a language I understood, and for me that was character. Costume, lighting, production design, camera movements—what were their character arcs? As long as I had a language I understood, it made it a lot easier to have a clarity and communicate my vision.

You’ve said of all the characters, you’re most like Brittany’s gay friend and running partner, Seth.

If I’m represented in the film in a concrete way, it’s Seth because I wanted to have a character who was a gay man who was at least presenting to have his shit together. I wanted this subverted traditional American family, with him and his partner and their children. That scene of them in bed with the kids at the end, I fought so hard to make sure we got that scene in the movie because it was important to me that the world see that image of two men in bed with their children whom they love in a paternal way. We ended up shooting that in a gym. They were actually lying on apple boxes with a Target comforter over them because we didn’t have time to film that scene, but it was so important to me. But Brittany is me in a lot of ways too.

Jillian Bell as Brittany and Micah Stock as Seth in Brittany Runs a Marathon.

How are you two alike?

This is a coming-out story. Brittany has rejected this idea of who she is. She’s been playing into this safe idea of what the world tells her she’s allowed to be, but she’s decided "enough." She’s at a breaking point and wants a more genuine life that feels authentic and real and doesn’t subjugate her to a supporting role. There was time when I felt like I was a funny sidekick in everyone’s life. I had to make a deliberate choice to become the lead in my own story. I changed the way I looked at and respected myself, the way I asked people to look at me and respect me, and some people made the cut to the next chapter in my life and some people didn’t. I was never going to be fulfilled if I kept holding myself back with this idea that I needed to be unthreatening and funny in order to survive in the world. I wanted to own my power and dignity, and do it in a way that made me happy and content.

The work I’ve done on myself coming from Georgia to New York is the exact same work Brittany is doing in this film. And what I’ve found showing this film around the country is that this relatability doesn’t stop with just us—that’s everybody. Everybody who sees this film is having some cathartic reaction and identifying with her in ways I couldn’t have even imagined.

What was the toughest part of directing?

The truth is, I loved it. I loved directing this movie. I got two hours of sleep every night and was never tired. There were challenges, but everyone involved was doing this because they loved it. The toughest part might be figuring out the second movie.

Brittany Does Cross Fit?

Brittany Does a Tough Mudder. Real Brittany and I used to joke when she tried things out in real life: “Is there a movie in this?" Brittany Gets Bangs? Is that the sequel? There'd be lots of lows in that story.

Brittany Runs a Marathon hits theaters August 23.