An overweight mother-of-four has become a successful fitness model at the age of 41 after shrinking five dress sizes. Maria Twomey, 42, of Watford, became a bikini competitor after swapping takeaways and fatty snacks for weight-lifting and intense workouts on the exercise bike. She has now left behind her job in nursing and has joined the ranks of professional fitness models, hitting the gym for three hours a day. Scroll down for video . Maria with Sean before she lost weight (l) and winning second place in the Miami Pro modelling comp (r) She discovered she was able to lift weights and complete high-energy sprints on an exercise bike . She said: 'I've had an incredible "mum makeover". I want other women to realise that you're never too old to completely change your life around - all it takes is some hard work.' Maria, who is married to Sean Twomey, 49, a dental technician, saw her weight increase while she was raising their children Jake, now 20, Conor, 17, Liam, 14, and Kaine, ten. She said: 'After having children, watching my figure was the very last thing on my mind. I put all my energy into dashing around after my kids instead. 'Sean and I fell into the habit of treating ourselves with takeaways. 'It wasn't that we were dramatically over-eating, but we let ourselves fall into a pattern of inactivity, and eventually I began to notice that my outfits were getting tighter and tighter.' By the time she reached her 40th birthday in the autumn of 2013, Maria was tipping the scales at 12st 7lb and was wearing size 14 clothes. She eventually slimmed to her lowest weight of 8st 7lb, and reduced her body fat percentage from 38 per cent to 15 per cent. Maria before with husband Sean and children (l-r) Jake, now 20, Conor, 17, Liam, 14, and Kaine, 10 . Maria, just before her weight loss, found that fitting seatbelts was getting more and more uncomfortable . She said: 'It was still a massive shock for me - it was the heaviest I'd ever been. 'Fitting seatbelts around me was getting more and more uncomfortable. Before too long all I could think about what how overweight I was. 'I'd pop down the gym every so often, but I'd never really exerted myself. I realised that if I was serious about losing weight and getting back in shape, I would need to have someone spurring me on, so I signed up for a series of personal training sessions. At first, even jogging on the spot left me absolutely breathless.' As the weeks wore on, Maria found her fitness increasing and although the weight loss was not immediately obvious, she discovered she was able to lift weights and complete high-energy sprints on an exercise bike. After she discovered personal training her fitness increased, and although the weight loss was not immediate . Eventually her personal trainer, who had willed her on from the start, said he had bigger plans and suggested she take part in a fitness modelling competition . She says her transformation has completely changed her life . She also completely changed her diet in a bid to trim down. Before her weight loss she typically ate a fried egg on toast for breakfast, followed by cheese and mayonnaise sandwiches for lunch, with a large jacket potato with cheese and beans for her evening meal. She would snack on Twix bars, crisps and fizzy drinks throughout the day. Her new diet saw her eat poached eggs for breakfast, lean chicken with sweet potato for lunch, and lean steak with salad for her evening meal. She snacked on portions of nuts throughout the day, and was careful to drink plenty of water. She said: 'In a year I lost four stone. I was so proud of myself. 'I'd set out to feel happy in my own body again, and I'd definitely achieved that. I was content to continue to maintain my slimmer figure, but my personal trainer, who had willed me on from the start, said he had bigger plans and suggested I take part in a fitness modelling competition.' Competitive fitness modelling challenges participants to tone their bodies and perform in exhibitions where they are judged on their physique and stage presence. After being encouraged by her family and friends, Maria took part in her first amateur competition, the Miami Pro in St Albans, in October 2014. The mother-of-four pictured after her weight loss, having fun in the sun with her nephew Alfie . She said: 'I was 41 and stepping on to a stage to pose for the first time in my life in a size six bikini. 'As confidence boosters go, it was hard to beat, and I was amazed when I was announced as the runner-up.' 'Reaching second place qualified me to compete in a professional category. Athletes train for years to reach that level, so I felt incredibly lucky.' Maria is will take part in her second competition on Sunday April 19 at the Miami Pro World Championships in St Albans. She is using the exposure gained from competing to launch a career as a personal trainer. She said: 'My transformation has completely changed my life. I have hopes for a new career, and my relationship with my family has got even better. 'I'm a calmer, more balanced person. I feel like I'm a better mum to my kids because I have more confidence and energy. 'I think it's important for people to realise that you can do absolutely anything if you put your mind to it - I'm proof of that.' Breakfast: Poached eggs . Lunch: Lean chicken with some sweet potato . Dinner: Lean steak with salad . Snacks: Nuts throughout the day, and is careful to drink plenty of water . Breakfast: Fried egg on toast . Lunch: Cheese and mayonnaise sandwiches . Dinner: Jacket potato with cheese and beans . Snacks: Twix bars, crisps and fizzy drinks throughout the day . Maria with her trophy having won second place in the Miami Pro modelling competition in St Albans in 2014 .
Maria Twomey, 42, of Watford, decided hit 40 and decided it was time for a change .
Wanted to slim from size 14 and signed up for personal training sessions .
Swapped takeaways and fatty snacks for weight-lifting and HIIT workouts .
In a year she went from 12st 7lb to her slimmest, 8st 7lb .
She's reduced her body fat percentage from 38 per cent to 15 per cent .
Now taking part in Miami Pro World Championships fitness model comp .