Maria Newstead, who worked at the Observer from 2016 to 2019 before taking up a job in public relations, shed 9st 8.5lbs in 80 weeks between January 2023 and July 2024.
Now far fitter, healthier and more active, the St Leonards-based 32-year-old is training hard for the Rob Burrow Leeds Marathon on Sunday May 11.
Maria and husband Simon, the Observer's sports editor until 2019 who now works for the Portsmouth News, will both undertake the gruelling 26.2-mile challenge in Yorkshire next month, with the aim of raising funds for the Motor Neurone Disease Association.
Maria said: "I've struggled with my weight for as long as I can remember, but it was getting to the point where it was seriously impacting my health and my happiness, and I knew something had to change.
"Even though I've been at my target weight for nine months now, I still can't quite believe I managed it - all the hard work paid off and I keep seeing the benefits in so many different ways, both mentally and physically. It's changed my life."
Due to a combination of working long hours in sedentary roles, eating for convenience and doing relatively little exercise, Maria saw her weight rise to more than 21 and a half stone.
Having at times in the past lost some weight only to put it back on again, in January 2023 Maria decided this time she would lose it for good and joined her local Slimming World group run by Liz Pryer.
By following the Slimming World food plan and significantly increasing her exercise, Maria made swift progress on her weight-loss journey.
Maria won her Slimming World group's slimmer of the week award 20 times and slimmer of the month award on five occasions, as well as the annual Miss Slinky and Greatest Loser prizes.
She added: "For many years I was adamant I could lose weight on my own, but joining Slimming World gave me the support network and accountability I never knew I needed.
"I wanted an eating and exercise plan that would completely overhaul my lifestyle, making long-term change and not just a quick fix, and that's what I found.
"I discovered a whole new world of healthy and home-cooked meals that I enjoyed and that could easily become part of a sustainable diet. With that and the support of my family, friends and Slimming World group, I knew this would be the time I lost the weight for good."
As well as eating healthily, key to Maria's success has been her commitment to exercise. Running, tennis, squash, badminton and gym workouts all contributed to her success.
In fact, the improvement in her running has been just as remarkable as her weight loss. Having taken around 54 minutes to complete her first 5k via a combination of running and walking early in her weight-loss journey, Maria progressed to running the same distance in less than half that time.
She joined Hastings Runners, a club which Simon has been a member of since 2019, in the early part of last year, and now regularly runs with fellow club members on Wednesday evenings and Sunday mornings.
As well as taking part in several club-only events, Maria has run the Bewl 5-Mile race, BBB10K in Battle and Rye Ancient Trails 15k, and in February completed her first half marathon in Tunbridge Wells.
Now she is stepping up in distance even further to a full marathon - a challenge which she is looking forward to, albeit with an inevitable degree of trepidation.
Maria and Simon have chosen to take part in the Leeds event as it's named in honour of Rob Burrow, the former Leeds Rhinos, England and Great Britain rugby league star who died from motor neurone disease last June aged just 41.
Simon lost his mum, Anne, a former teacher at Westfield and Battle & Langton primary schools, to the same neurodegenerative disorder - for which there is currently no cure - in July 2022.
Maria added: "Motor neurone disease is such a brutal condition, and to see Anne go from a perfectly healthy woman to being unable to eat, drink, move or speak was utterly heartbreaking.
"The Motor Neurone Disease Association was so helpful to us during Anne's battle with the condition, and we've since been looking for a way to help them with their vital work to support other families experiencing what we went through and to one day hopefully find a cure.
"Rob Burrow was an amazing man and an inspiration to so many people living with MND, so taking part in his event felt like the ideal fundraising challenge for us.
"If you'd said to me at the beginning of 2023 that I would one day run a marathon, I would never have believed you. But now, having achieved my weight-loss goal, I feel like I can do anything I set my mind to - and the marathon is next."
Anybody wishing to donate to Maria and Simon's cause can do so via their online fundraising page at https://www.justgiving.com/page/simon-maria-marathon.
Liz Pryer runs her Slimming World groups from Holy Redeemer Church Hall, Upper Church Road, St Leonards, every Thursday at 9.30am, 11am and 5.30pm.