"When I saw those legs I nearly died. I rang the model agent and said 'Why is that girl walking down the runway when she's clearly not healthy?" now former Marie Claire editor Jackie Frank said at the time.
Now 26 and with a young son, van den Dungen has become so sick of people commenting on her weight that she's gained 10kg.
"I wanted to gain it because I'd had enough of people saying that I was so skinny," she told news.com.au.
"I've put on a total of 10kg and I'm really happy about that. I finally have a healthy BMI, it's the first time I've been in the 18-25 range since I was 15," van den Dungen said.
"I've grown up my whole life with people telling me I'm skinny, even though I was healthy and doctors and health professionals told me I was fine and it impacted me emotionally every time."
Van den Dungen says she has always struggled to gain weight. Even after the birth of her son - a time when many new mothers are seeking to shift kilos - she was trying desperately to gain some.
"I remember crying about it in the weeks after having my son. I was very emotional," she said.
"I went to the doctor and he said 'Don't worry about it, you've always been small framed. Just make sure you're eating healthily and I'm sure it will come back'."
But it never did. Every time she gained a couple of kilos, stress or intense travel for work would cause it to slip away.
"My body finds it really easy to lose weight and hard to put it on," she said.
"I went to the doctor again and he said 'this is how you are, but if you want to put on weight, you have to change your diet and exercise'."
She changed her training and added a protein shake to her lunch for extra calories.
"I was working out for 1.5 hours in the gym, I was overworking myself. I was constantly injuring myself. I tore muscles. So now I only do 45 minutes and it's all weight training.
I thought if I can't hold fat very well, I may as well hold muscle," van den Dungen said.
"I need to make sure I don't push my heart rate too high for too long. So my workouts go around pushing weights and squats and doing things that don't bump my heart rate but build muscle.
"I love tricep dips and bench pressing. I never thought I'd ever say that."
Although the stereotype of the critically underweight model exists for a reason, van den Dungen says most models are naturally thin.
"It's not something that people really understand because a lot of models are like myself. We all struggle to put weight on and a lot of models are constantly fighting to not lose weight," she said.
"People put models down and say they have anorexia. And yes there are eating disorders in the industry but a large majority of models are just naturally thin.
"I've spoken to many models who say it's hard when people criticise your weight. I want to show that you can gain weight in a healthy way and still fit the criteria for a model."
The fashion industry has attempted to put some measures in place to promote positive body image messages and ensure only healthy models secure work.
Last year, Australian Fashion Week organisers required all models on the runway to be over 16 years old and banned models who "would be considered to be unnaturally or extraordinarily thin or suspected of having an eating disorder".
In 2015, the French government introduced a law requiring models who want to work in France to provide a doctor's certificate confirming their overall health and an appropriate body mass index.
The law also required any digitally altered photos to include a disclosure declaring they had been Photoshopped.
Those to fail to comply face six months jail and a €75,000 ($117,000) fine.
Van den Dungen has no plans to walk in this year's Australian Fashion Week, which starts in May.
For now, she is enjoying her new-found strength and spending time at home with her son.
"I wanted to prove to myself that I could be stronger. I might forever be small-framed, but I can be strong," she said.
"I feel like I've achieved it. I'm really proud of where I've gotten to."
