Unless you are particularly blessed, chances are there have been times in your life where you’ve felt inadequate, out-of-shape, or lonely — if not all three. There have been films that have addressed these kinds of issues in the past, but Brittany Runs a Marathon tackles them in an unusually frank manner.

Jillian Bell stars as Brittany, an overweight woman scraping her way by in New York City. She has a low-level job at a theater, uses humor to deflect from almost any real human interaction, and shares an apartment with Gretchen (Alice Lee), who’s skinny and status-obsessed.

When her doctor says she needs to change her lifestyle to be healthier, Brittany takes inspiration from her neighbor Catherine (Michaela Watkins) and decides to give running a chance. Buoyed by positive results and new friendships with Catherine and Seth (Micah Stock), she soon sets a goal of running in the New York City Marathon.

Written and directed by Paul Downs Colaizzo and inspired by the true story of one of his friends, the film is equal parts funny and dramatic. With Bell in the role, Brittany is able to mine humor from almost any situation, and the character’s insecurities — and her reactions to those insecurities being exposed — lead to some uncomfortable scenes that most filmmakers would avoid.

Colaizzo isn’t interested in making the typical studio film full of pratfalls or other comedy lowlights. Instead, he layers in the drama of real life to paint a full portrait of Brittany and the supporting characters. Among the topics brought up in the film are a custody battle, same-sex parenthood, financial woes, and more, each treated as things of genuine interest rather than a way to propel the plot forward.

Ultimately, it’s the relationships in the movie that make it a winning film. Bell, Watkins, and Stock make for an engaging trio, with each getting moments of true introspection. Bell also works well with Utkarsh Ambudkar, who plays a freeloading house sitter, and Lil Rel Howery, who plays Brittany’s brother-in-law with whom she video chats often.

Bell, who’s mostly played supporting roles in the past, shines as the lead. She gave full commitment to the role, losing weight during filming so that she could take the same journey as Brittany. But more importantly, her personality is magnetic, drawing viewers to her no matter what’s happening to the character.

Whether or not Brittany actually accomplishes her goal in Brittany Runs a Marathon is beside the point. The film inspires, thanks to its focus on both internal and external change, and how each needs the other for true success to come.