Mary McCarthy is one of the most recognisable faces in UK running right now. But the 2:50 marathon runner and content creator behind "Beat the Boys" didn't appear from nowhere – she's been quietly building for nearly two decades.
This week on The Runna Podcast, Ben and Anya go behind the content and the times to understand the engine, the mindset, and the self-belief that got her here, and where she's headed next.
Watch or listen to the full episode to hear the full conversation.
The 19-Year Base Nobody Talks About
Before the viral videos and marathon times, there was a girl in Sheffield swimming twice a day, racing cross country on Saturdays, and running miles on weekend mornings– alone, no headphones, just for the love of it.
Mary's athletic base goes back to age eight. Competitive swimming, Yorkshire cross country titles, university athletics – all of it built long before a single person was watching online.
It's why her progression in the marathon has been so fast, and it's something she's thoughtful about when people ask how she improved so quickly: the early mornings, the fuelling, the consistency: none of that really shows up in a TikTok.
This episode is a chance to see behind that.
Training First, Content Second. Always.
One of the clearest things Mary says in this conversation is how she thinks about the relationship between her running and her platform. Training is always first. Content is always second.
She's not going out to make a video. She's going out to train, and the content is the byproduct. That distinction, she says, is a big part of why it's worked. When performance is the priority, everything else follows.
It's a useful frame for any runner who's started to feel like their running needs to serve something else whether that's social media, a time, or a goal set by someone other than them.
What "Beat the Boys" Actually Means
It started as a bit of fun, but it resonated in a way Mary didn't fully anticipate.
In this episode she talks about where it came from, who it's really for, and why it goes well beyond running. The women who message her aren't always runners. Some of them just needed to see someone backing themselves – quietly, consistently, without making a big deal of it.
That's the thread running through everything she talks about: staying in your own lane, measuring yourself against your own journey, and doing the work without needing external validation to make it real.
"I Started Running Because of You"
Mary is clear about what matters most to her. Not the times, not the following – it's the moment she meets someone who tells her they started running because of her.
She talks about a Saturday night in a pub, weeks after racing, when women came up to her to say she was the reason they ran. That feeling of having moved someone from the sofa to the start line is what she describes as the actual goal.
It's also what makes this episode worth sharing with anyone who's been thinking about starting, returning, or finally signing up for something they've been putting off.
Still Just Getting Started
Two years into marathon running, Mary has already run 2:50, and she's open about what she's working towards.
The goal isn't to be the fastest woman in the country. It's to find out how fast she can go on her own terms, and on her own timeline. She talks about what that looks like in practice: the kind of training block where everything – eating, sleeping, recovery – is pointed at one thing, and the quiet satisfaction that comes from showing up fully prepared on a start line.
She's only just getting started.