A 288-pound woman, who became the heaviest to ever complete a marathon last month - has set her eyes on the Ironman.

Ragen Chastain, 41, said that she wanted to raise awareness that there are runners of all shapes and sizes.

'I was looking around for other plus-size people who had done marathons, and I saw a lot of people who started the marathon but didn't finish it,' she told People.

Ragen Chastain, 41, said that she wanted to raise awareness that there are runners of all shapes and sizes

At 288 lbs, Chastain became the heaviest person to ever complete a marathon (pictured) this year - has set her eyes on the Ironman

'So I was just really inspired by the idea of being plus-size and finishing the marathon, and the visibility that would create for other people who wanted to try it and thought they couldn't because of their size.'

After just 20 weeks of training, the former non-runner successfully finished the Seattle Marathon, making her the heaviest woman to ever run a marathon.

Unfortunately, as Chastain wasn't aware she was breaking a record when she entered, she didn't pre-arrange the event with the Guinness Book of World Records, so is not an official record holder.

If she wanted to enter the record books, she'd have to run another marathon.

But with the pain of the Seattle run still a fresh memory, Chastain decided she needed a new challenge; she would become the heaviest woman to ever compete in an Ironman challenge.

Chastain said she wants to raise awareness there are runners of all shapes and sizes

After just 20 weeks of training, the former non-runner successfully finished the Seattle Marathon, making her the heaviest woman to ever run a marathon

'It seemed like the ultimate expression of pushing outside of my comfort zone. So I decided to do the second marathon as part of the training for Ironman Arizona.'

The Ironman Arizon, which takes place in November, kicks off with a 2.4-mile swim, followed by a 112-mile bike ride and ending with a full marathon. And as part of her training, she also picked up the Guinness World Record at the Mainly Marathon in Sanford, Maine.

Chastain says she wants to compete, not just to push herself, but to push the limits of what people expect of those over a certain size.

'Nobody of any size is obligated to participate in fitness, but I think that we should all be welcomed,' Chastain said.

The inspirational runner's fitness journey has been praised by many, but has also attracted a few critics who accuse her of glorifying obesity.

But Chastain says for every hurtful comment, she'll receive an email that lets her know she's doing the right thing.

One email she received from an overweight woman who told her: 'I've always wanted to run but I was told that I couldn't do it at my size but I saw what you did and signed up for a 5K,' or 'I'm going to marathon now.' So much of it is giving people role models.'