Mele, right, lost 65kg through daily exercise and cutting out soft drink and other processed foods.
Mele Osai always knew she was overweight.
At 14-years-old, she weighed 135kg at her heaviest, and would consume enough takeaway food to feed multiple adults.
But it wasn't until a 20 minute walk home from school drove her to exhaustion and forcing her to sit down and rest, that she realised just how badly her size was impacting her health.
Feeling like an "outcast" and unable to fit in to the same clothes as her school friends, Mele's doctor warned the teenager that diabetes was imminent unless her lifestyle changed.
Too shy to exercise in public, Mele started an exercise regimen in her own backyard.
Living most of her childhood and early teenage years "on the computer and laying around", Mele knew exercise would only form part of her weight loss mission.
"I've always been a big girl and always known that," she said.
"I have a big appetite and I'd pair that with bad food choices and living a sedentary lifestyle."
Mele, who lives with her family in Sydney's west, said she could drink at least 2L of soft drink each day, and that her portion sizes weren't that of a healthy teenager.
"When we had takeaway I'd order an amount that could feed multiple people," she said. "I also drank a lot of my calories through flavoured milks and milkshakes.
"I'd eat two or three sandwiches at a time and always going back for seconds at the dinner table.
"My choices a lot of the time weren't necessarily bad food, but I ate a lot of it."
Now 16, Mele - who currently attends Mount Annan High School - said her 65kg weight loss was spread over two years.
Completely changing her diet to include vegetables, protein and daily exercise - the Year 11 student promised herself not to fall in to the trap of fad diets during her mission.
"When I was younger the fad diet appealed, but I think I knew better," she said.
"They didn't seem enjoyable and I didn't see anything good about having shakes or replacing meals with a drink.
"I started incorporating more vegetables and fruits and making better choices. Diet is the biggest factor in weight loss."
Mele now starts her day with a "big bowl of oatmeal with yoghurt and fruits".
Admitting she doesn't really get hungry during the day, she will snack on fruit and water until dinner - which is usually made up of a lean protein (chicken/beef/fish) with lots of vegetables, rice, potatoes and some sliced avocado.
Not wanting to lose any more weight, Mele is now concentrating on strengthening and toning at the gym through her love of weights.
Attending five or six days each week in between her retail job and school, Mele also incorporates long walks for cardio.
"All the magazines make it complicated," she said.
"I just want to help promote a healthy way to lose weight.
"Society is obsessed with weight, and I think that's sad especially for young people ... because a lot of young people think they need to do extreme things to lose
In Australia, one in four children are overweight or obese. Mele, who hopes to go to university and study in the fitness field, said her parents never forced her to lose weight, which she is grateful for.
"I was the outie in the family ... I stuck out like a sore thumb," she said.
"I see a lot of parents pressure their kids in to doing things to lose weight.
"I feel very grateful they [parents] left the decision to me, because they knew one day I would make the change.
"But when I made the decision, I was all in and I knew I was going to do it. It needs to be for you and not for someone else.
"There were times where you struggle and not see results, but that's the moments you keep pushing. Don't deprive yourself, because you will miss out on memories at special occasions.
"Accept that no one is perfect and that you will slip up, but tomorrow is another day to get back on track."