A year later, she completed her first Ironman race in Taupo.
Running has become a big part of her life. She is now a registered running coach with Athletics New Zealand and she's also an accredited coach through Athletics Australia.
"I've changed my whole way of thinking and have come to realise that it doesn't matter what you look like, just as long as you are a good role model."
Ironman Oceania managing director Dave Beeche said King was an example of someone not only taking on a challenge but impacting on their personal health.
"Alison's story reminds us that each and every participant will have their 'back story' as to why they are on the start line - we want each and every one of those experiences to be memorable ones."
- Read more about the Air New Zealand International Marathon in Saturday's edition.