"As we were watching my husband Rick do it - he finished his second marathon this year - we saw a group walking together, they would rotate, each taking the lead. Who says you have to run the marathon? We can walk and have fun with others."
The group were all dressed in the same T-shirts and finished the marathon together.
"We thought we could do that," says Nataria.
"We were really inspired that day."
The plan was hatched and they have since recruited members to their walking group with the ethos that no one gets left behind.
In June they started training with one weekly walk. They meet at the Rotorua Aquatic Centre and complete "wacky group goals" such as bootcamp training on Hospital Hill, dressing in a theme, bringing other whanau members along.
From October the training will step up a notch - they're being guided by Doris Bragg, who has completed 21 Rotorua Marathons.
The philosophy behind them is entrant level - you can be a complete couch potato and they will endeavour to get you across the finish line.
"We only want to do events significant to us and this is our lake, we couldn't get a better connection," says Leanne.
"Being Maori there's an ancestral connection to the land. This is a significant way of connecting our people to their land. Our walks will be marae to marae - there are 17 around the lake, we'll be visiting them with positivity."
For Uncle Antz, as Anthony Ngawhika is known, there's another 50 thrown in - he has recently turned 50.
"These girls can walk," he says.
"I've already noticed a lot of changes since I started walking, now I can walk and talk - before I was too busy breathing hard."
He said he weighed in at a hefty 236kg before he started exercising. Last December he walked 21km in an IronMaori team; he's now weighing in at 179kg and he's set a goal to be between 120kg and 130kg come race day.
"This has been a bit of a journey. The whanau is awesome and that's why I've stuck with them. They're fun to be around and they motivate me."
Nataria says it's people like Antz who embody the 50/50 Whanau spirit - the goal is to complete, not to compete, and they will do all they can to get the group across the finish line together.
"A lot of our whanau never saw themselves as completing something. People say about Mt Ngongotaha 'that's my mountain' but they've not been up it, or 'that's my lake', we're going to get them around it."
Those signed up so far are: Nataria Rolleston, Leanne White-Haverkamp, Erin Thompson-Pou, Darcelle Jensen, Bridgitt White, Michelle Phelan, Noeline Takahi, Anthony Ngawhika, Nesee Smith, Evalyn Berryman, Ngaire Gordon, Glenys Strachan-Courtney, Maxine Courtney, Linda Agee, Haley Stewart, Waitangi Herewini, Tiria Shaw, Hoana Teaki, Helen Messenger, Erinne Pou, Te Awaroa Raerino, June Easton, Tanya White, Denise Wibrow, Arapeta Tahana, Wiki Mansell and Kiri Brooks.
If you want to join the 50/50 Whanau, contact Leanne on 0275 253 826 or sendit2lee@hotmail.com.