Two years ago Larissa Smith weighed 17 stone and got out of breath just walking up a flight of stairs.

But now, six stone lighter, the 33-year-old is weeks away from tackling her first marathon in Brighton on April 17, with the three friends and training partners she met through her Bungay running club.

Miss Smith, who is an HR advisor said: 'A friend at work challenged me to do the Beccles Triathlon to give me something to focus on and aim for, so I went to the gym and tried to run on the treadmill, but I couldn't even manage one minute.'

Undeterred she joined Slimming World and the Bungay Black Dog Running Club's beginner sessions to help give a better structure to her running - and the weight rapidly dropped off.

'I was really worried that I wouldn't be able to do it and felt quite nervous about going, but everyone was lovely and so friendly and encouraging.'

From small beginnings, Miss Smith was gradually able to run further and soon confident enough to join in with the club runs.

It was on these social runs that she met up with Lucy Johnston, Loretta Thurston and Emma Cowley.

She said: 'We just got chatting and no-one has been able to shut us up since. They were so supportive to me, I would never have done it on my own so I was lucky to have them pushing me on.'

The ladies started going on their long park runs together on Sundays and began entering local races together.

When Mrs Johnston and Mrs Cowley gained places to run last year's London Marathon, the four of them vowed to support each other with their training programmes.

'As we all trained together last year, we thought it would be lovely to carry on and all four of us enter a marathon that we could run together, so we chose Brighton,' said Miss Smith.

'It's great to have the others, there's non-stop chatting all the way round and if someone is having a bad day, we pull each other round.'

Miss Smith also manages to fit in swimming training and cycling having stuck to her original challenge of competing in the Beccles Triathlon.

She and Mrs Johnston are now setting their sights on an Ironman triathlon, which comprises a 2.4 mile swim, 112 mile cycle and finishes with a full 26.2 mile marathon.

She said: 'I've caught the bug. I really love the combination of exercise, which is something I would never have said two years ago.

'We hope to take part in one in 2017. Don't ever think you can't do something because believe me, you can.

'I am quite a determined person but never in a million years did I think I could run a marathon, It just shows you can still do it whatever shape and size you are.'

Are you taking part in a marathon? Email louisa.lay@archant.co.uk