Before the customary first weigh-in, trainers Shannan Ponton and Steve 'Commando' Willis wanted to test the mental strength of the 'Ararat champions'.

"So far you've all shown plenty of ticker, but it is time to prove that you've got what it takes to get to the house," Ponton explained.

Contestants were then shown a 50 metre cliff with a custom built flying-fox, constructed especially for The Biggest Loser.

"All you've got to do is jump off the edge," The Commando told the terrified looking Ararat locals.

Cameron Brown voiced his concern immediately about the task following a bad experience with heights as a child. The supermarket manager said if he was going to participate he wanted to be the first one to take part.

After some encouraging words from Shannan and with the flying-fox the only way into The Biggest Loser house Cameron mustered the courage to take the leap.

"To have this opportunity put in front of you to say step off the cliff and change your life, it is a pretty easy decision," Cameron said.

"Never in a million years did I think I'd step off the cliff, but to know I did...it was a pretty defining moment in my life - the change starts now."

All 13 of Cameron's team mates followed suit, with some lapping up the experience while others 'hung on for dear life'.

Mary Reid provided some comic relief when she grazed some rocks on her way down the flying-fox, tearing a hole in her pants in the process.

"I don't know if Australia's ready to see that just yet, we've only just met," Shannan joked.

Laughter soon turned to tears however, with the contestants forced to face their family, friends, work colleagues, the town and...the dreaded scales.

Mother of two Katrina Pianta best summed up the feeling of the room.

"My greatest fear with the scales is other people knowing about the number," she said.

"I know it, but if nobody else knows it I can just go along pretending that it's not as bad as it is."

Katrina was first to weigh-in, recording a starting weight of 131.1kg.

"It is a number I don't share with anyone. Not a soul," she said.

"I don't want to use the word 'disgusting' but in a way that's how I feel about myself, disgusted.

"I was always the fat mum at the school gate. I don't want to say it out loud but I think (my kids) are probably ashamed of me.

"I am taking this time to be selfish for 12 weeks, but when I come back it will be better. We (husband Garry) will be a dynamic duo."

Up next to weigh-in was Cal Evans, who tipped the scales at 131.6kg.

Cal was joined on stage by his young son, and he revealed his two children were the motivation behind joining The Biggest Loser.

"This is why I am doing it. He needs a dad," he said.

The youngest contestant of the series Caitlin Munday was up next and recorded 134.4kg.

"I'm disgusted, how can I be 17 and weigh that much? It is just ridiculous," Caitlin said.

"I feel like I am taking a back seat in my life."

Matt Dalton weighed in at 122.2kg and told the audience his aim was to lose weight to start a family.

"It is a big number and I shouldn't be anywhere near it," he said.

"I want to have children with my fiance and we can't do it at the weight we are at.

"Jan is my world, she is my favourite person. I have to lose the weight first, come back and help Jan do it."

After the scales flashed up 117.6kg for Natalie Wohlers her emotional history brought many to tears.

"I have had a lot of things happen in my life that has brought me to that. In 2001 when I was 26 I got cancer of the thyroid and ever since then I have had trouble controlling my weight," she said.

"I know I'm not the only one that has been through it. You just have to get in there and deal with it and when you are left alone, what other choice do you have?"

Natalie's promise to change her life and be around for her children brought rapturous applause from the packed house.

Up next was Sharon Basset who weighed 109.8kg, but was determined to change that and become a 'sexy mumma'.

Fellow mother Shannon Woolley was the lightest of the contestants at 97.2kg, but conceded she wasn't being a good enough role model for her children.

"I am doing nothing I want to do with them, I'm giving them the life I want for them, but I'm not in it with them," she said.

Next to weigh-in was husband and wife pair Kerry (141.6kg) and Toni Stockwell (124.2kg).

Kerry said he and his wife would be relying on each other a lot in the house.

"To do it together I think we are a bit lucky, because we've got each other to lean on," he said.

After revealing her weight was 121.7kg, Jane Jantzen moved her family as she shared her feelings.

"It is hard enough to admit that (number) to yourself, let alone your family and friends," she said.

"I love them all to death, but I am not doing this for them, I am doing it for me."

Weighing in at 125.6kg and always the character, Rodger Turner had the audience chuckling when he revealed how he takes his dog for a walk.

"I take the dog for a walk...we go out the bush, I let him off, then hop back in the ute!" he said.

Cameron Brown said he was determined to change his life and his 146.4kg weight.

"I was the first one to jump off that cliff, I was the first one selected to go into the house and it is a massive privilege to do this for Ararat," he said.

Craig Booby tipped the scales as the heaviest of the series at 183.4kg.

"There's a lot of people here - friends and family - I never wanted to admit how much I weighed and how I got this big.

"I guess the past five or six years I let myself go a bit, I was engaged to get married and that fell through. I thought why bother and gave up on life to a degree."

Craig revealed he would often be the first at the pub and the last to leave as he 'drowned his sorrows'.

With 13 contestants weighing in, that left just one to go - Mary Reid.

When the 48-year-old stood on the scales she broke the record as the heaviest female contestant in Australian Biggest Loser history, weighing 181.5kg.

Mary, who has already become a crowd favourite on social media, drew a standing ovation for her honest and candid comments about her life.

"It is hard getting out of bed every morning and holding on to the wall to get around the bed so you don't fall over, until your legs settle under you," she said.

"It is hard to stand in the shower to even clean yourself because it is a lot of weight for these poor old feet.

"I drag myself to work and put on my best face for the customers and then I drag myself home and I scream at my husband because I am so tired.

"Then I sit down and that's where I stay and we do it all over again the next day."

Mary talked about the need to renovate her family house to accommodate her growing weight.

"...And all this before I am 50," she said.

"I've just got to do something now. You diet but you do it on your own in case you fail and you know you will, because you don't have anyone in your corner.

"Now I feel like I have all you guys in my corner as well, because you all know now that this is my journey and you're going to be there for me too and I won't have any excuses."

The contestants have now made their way to Sydney where they were met by The Biggest Loser host Hayley Lewis who has issued a 'pre-house warming challenge called The Punisher'.

Sunday night will see the contestants battle the steps of the Sydney Opera House, with the bottom two teams facing elimination.