A Midland mum who was once so overweight she couldn’t even fit her young son on her lap is getting ready to take part in the AJ Bell Great Birmingham Run 10k after an astonishing transformation.

Cat Byrne will be cheered on by five-year-old son Orson, who she credits with inspiring her to lose 11.5 stones, when she takes part in the city’s biggest celebration of running on Sunday 3 May.

Two years ago, Cat, from Bromsgrove, weighed 23.5 stone and struggled to play with her son, who couldn’t even fit on her lap.

“I felt really disappointed in myself and embarrassed that I was struggling to do basic things because of my weight,” says Cat, a UX/UI Designer. I’ve always been overweight but between Covid lockdowns, pregnancy and then being a new mom the weight just kept creeping up. For the first few years after having my son I kept telling myself I needed to make healthier choices to be a better role model for him as he grows up. I want him to see that eating good food and exercising to keep our bodies functioning properly was normal.”

So, in January 2024 Cat joined a local weight loss group. Ten months later she’d lost nine stone. At that point she decided to start running to help her reach her final weight loss goal and improve her fitness.

“I knew I wanted to become more active as I got closer to my goal weight, but I didn’t know where to start,” Cat explains.

“It was only after following a couple of friends’ and families’ running journeys and seeing how much it helped not only their physical but also their mental health that I thought I’d give it a try.”

At first Cat was so embarrassed at her lack of fitness that she decided to start running on her own at lunch times when the roads were quiet.

“I would say I was one of the least active people you’d have ever met before October 2024,” she recalls.

“But I kept going with the calorie deficit, running and added in some weight training and by April 2025 I had lost 50 per cent of my body weight and gained a whole lot of life.”

Cat says her son Orson was her driving force.

“Oh, he is absolutely my main inspiration. I want him to grow up seeing exercise as something to look forward to. He sees me excited to go for a run and proud of myself when I get back. Sometimes when I’ve had a ‘bad’ run I tell him that I didn’t manage to do the run in the way I wanted to but that’s OK, I’m still proud of myself for getting out and trying and that I’m looking forward to giving it another go next time. I want him to know that exercise isn’t punishment or something we do because we have to but something we do because we want to. I now enjoying being able to run and play with him and inspiring him to exercise and be proud of what our bodies are capable of!”

Until now the furthest Cat has run is around 5K. So why did she decide to sign up for the AJ Bell Great Birmingham Run 10K?

“I decided to challenge myself so I can look back and say “remember when you couldn’t manage that first 60 second run of the Couch to 5k? You kept trying and look how far you’ve come.

“It keeps me striving to be better for myself and my son. He’ll be at the Great Birmingham Run cheering me on and seeing his mum doing something she’s worked hard to be able to do.”

Find out more and sign up for the Great Birmingham Run 10k or half marathon on Sunday 3 May, and the Junior and Mini events on Saturday 2 May, by visiting greatrun.org