Brittany Runs a Marathon opens with Brittany, played by Jillian Bell, going to the doctor. She wants to scam an Aderell prescription, but the doctor isn’t buying her story. He suggests she get “healthy” and lose 55 pounds, a figure Brittany calls “the weight of a Siberian Husky.” It’s a funny moment, that also leads Brittany to decide to train for the New York Marathon.
Over the course of the film, Brittany — and Bell — loses 50 pounds. Nights of binge drinking and Dunkin’ Donuts turn to glasses of water and salad after salad after salad. She makes friends through running and her life gets noticeably better. It’s sweet and inspiring — but the story didn’t need to tie the success of running the marathon (a major accomplishment) to weight loss.