They are participating in the Half A Tonne Gone Challenge, which was devised by Ward 3 nurse unit manager Ian Wilson after he spotted himself in a full-length mirror on a Christmas shopping trip last year.

He thought he needed to lose a few kilos and put the same challenge to his colleagues at the ward’s Christmas party in December, daring them to lose 500kg collectively in 12 months.

Over the Christmas break, Mr Wilson decided to put his money where his mouth was and offered a prize of $500 from his own wallet to the individual who lost the biggest percentage of their body weight.

The word spread through the hospital and now 119 staff members have signed up, with about 13 teams (from different wards and units) listed.

“It’s been quite a remarkable response,” Mr Wilson said.

“I think people have been thinking about it, wanting to do it, and this was very timely.”

The hospital’s director of medical services, Barbara Moritz, has put forward another $500 for the team with the biggest percentage of weight loss.

Following the weigh-ins it was found the average participant is 167cm tall, weighs nearly 91kg and has a body mass index (BMI) of

more than 32 – putting them in the obese category.

Two personal trainers among the hospital’s staff have offered their services, other employees have given advice and resources, and the staff gym has offered free memberships to help the challenge participants along the way.

“It’s over a 12-month period, so I’m hoping it will be a long-term change,” Mr Wilson said.

After just a few weeks people had already reported weight losses, with Mr Wilson himself losing 5kg since Christmas.

He believes his workmates will stick with the challenge.

“I’m encouraged, just because there was no pressure for anyone to get weighed ... and just from what I’m hearing there’s going to be a fairly high retention rate,” he said.

The winners will be announced at the ward’s Christmas party in December.