Mr Whitaker is calling on sponsors to donate a set amount of money for every person he passes.
"It's more about raising awareness that [firstly], people are suffering from kidney diseases," he said.
"And for parents, to let them know that yeah your kids are sick, but ... they're still strong. They can still run a marathon."
All funds raised will go to charity Kidney Health New Zealand.
Mr Whitaker was born with a urinary tract defect that was not diagnosed until he was a 3-year-old. When he was 14 years old, a specialist recommended that his left kidney - which had been an issue throughout his young life - be removed.
In turn he decided that one of the best things he could do was to help others who had been in a similar situation.
"As a child I suffered from kidney disease. Growing up as a teenager, I always thought I wanted to help kids who had been in my position," he said.
"But also helping ordinary kids to better understand it and to raise awareness of it. If you eat well, exercise and look after yourself, you can prevent getting kidney disease."
Mr Whitaker has called his mission the One Kidney Challenge and has set up a page on the Give-A-Little website for people to donate to.
He has also created the One Kidney Facebook page to promote the cause and has already had a small number of donations; but would like to get some businesses on board to sponsor him on the run.
On the web
givealittle.co.nz
Marathon effort
* Full marathon: Starts at King Edward Parade, Devonport, 6.10am on Sunday, Oct 30.
* Half marathon: Starts at King Edward Parade, Devonport, 7am.
* Quarter marathon: Starts at Gaunt St, 6.45am.
* 5km Run & Walk: Starts at Sarsfield St, 9.45am.
* Kids' marathon: Starts at Beaumont St (near cnr Packenham St), 10.45am.
Both half and full marathon entries are now closed.
