Even in childhood, she was always on the larger side and often would feel alienated because of her size.

And even into her adulthood, the stigma of being told she was "lazy" and "horrible" for being overweight was hard to stomach.

"I took after the larger side of my family from when I was a little kid," she said.

"As a child, we were always told to eat what was on your plate and not really eat until you were full.

"And I think that kind of attributed to the fact that I got bigger and bigger over the years."

Obesity is a serious, chronic, relapsing disease with a high prevalence and a substantial unmet medical need.

In light of World Obesity Day on March 4, it was important to highlight the condition as greatly misunderstood, with patients often subject to high levels of stigma, discrimination and negative impacts on both mental and health-related quality of life.

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A feeling Mandy knew all too well.

At her heaviest, she found herself struggling to find her place in society and in her own world view.

"It was quite depressing really," Mandy said. "I was bullied a lot for being bigger and different throughout high school and that was quite difficult to deal with."

But there were some times when she felt her life finally "getting back on track".

"When I got my first job, I did find there were times when I would lose weight," she said.

"I don't know if it was the stress or what it was, but I was never really sure what made me lose the weight, but I would always put it back on."

It wasn't until falling pregnant with her son that Mandy copped the full brunt of the obesity stigma.

"I was at my biggest when I fell pregnant even though I had lost weight here and there," she said.

"At my 12-week scan, I had lost a little bit from being so sick with morning sickness, but I was told my baby was bigger than normal and that I needed a diabetes test done.

"I did that multiple times throughout my pregnancy and each time my numbers were perfect.

"When I actually gave birth, I was told by my nurse that my 10 pound two (4.6kg) baby was that size because I was obese."

"My baby was healthy and I had no issues, but speaking to another midwife later on, she told me it was genetic."

Regardless, Mandy felt the weight of the midwife's words come crushing down.

"I think becoming a mother was a big turning point for me because I was always worried my child would turn out the way I did and struggle with their weight the same way I had," she said.

"I wondered how I would deal with that if I can't even fix my own problems. "I wanted to try and be the best mother I could.

"Being told it was my fault my baby was big was heartbreaking and disheartening to hear."

Research from the Diabetes Obes Metab has shown up to 70 per cent of the causes of obesity can be linked to genetics and the physiology that our genetics determine

This means family history and ethnicity can be strong predictors of weight gain and overweightness throughout life.

Obesity researcher Brian Oldfield said people living with obesity are often grappling with significant barriers to weight management beyond stigmatisation, including miscommunication and a lack of a formal medical diagnosis.

"While there is no doubt that personal lifestyle choices can lead to overweight and obesity, we as a community, are largely uninformed about the genetics and biology that dictate how easy it is to gain weight and how hard it is to lose it," he said.

"If we understood better the dramatic, irrepressible physiological changes that occur in our bodies after weight loss that tend to draw us back to our original weight, we would be less inclined to judge those who find this task difficult."

Mandy said it took taking a doctor who would listen and a weight loss routine that worked for her lead her to lose 30kg.

And she's managed to keep that weight off for the last six years.

"I tried a lot of different diets and ideas to lose weight, but a keto diet was what worked for me," she said.

"I had a lot of help from my doctor, which I would recommend to anyone thinking of doing it, and it was good to have that support.

"Obesity isn't all about a lazy person who can't be bothered exercising, it's genetic and some people are born with the struggle of being bigger."

This year's World Obesity Day is calling for a critical re-evaluation of the way Australia is supporting people living with overweight and obesity, in order to allow those facing this chronic disease to shake off the shackles of shame and judgement.

In doing so, a new campaign is calling on the community to overhaul how we approach, think of, lean into conversations on and manage obesity to foster a society where more individuals are supported by seeking help.

For information and helpful resources on overweight and obesity, visit truthaboutweight.global