At her heaviest she weighed 154kg, but it wasn't until she boarded a flight two years ago that she reached "breaking point".
"I needed two seats, I needed a seatbelt extender, It was horrible and definitely the wake-up call that I needed," Lavende told The Morning Show.
"That was my motivation to be like 'OK, you need to change'."
She was on diets, had gone to dietitians, nutritionists and doctors to work out where she was going wrong, before opting for a gastric sleeve weight loss procedure in 2018.
It involved removing 80 per cent of her stomach. After finding a meal plan that worked for her, combined with a rigorous workout schedule, she went on to lose more than 90kg and is now happier than ever.
"This wasn't a diet for me, it was a lifestyle change. I cut out all junk and fast foods, I don't do carbs, I don't eat sugar and I work out every day. This is a new lease on life."
She said Barbie was always her reward and inspiration throughout her journey.
"My obsession with Barbie began as a child and has continued into my adult life," she told the programme in a separate interview last year.
"I used to have over 200 dolls as my parents used them as an incentive to go on a diet and lose weight."
The costume designer has since started an Instagram page which she said helps hold her accountable.
"This page is all about happy, positive vibes. Obviously I love Barbie, I love pink, I have been on massive weight loss journey [which] I am still doing every day," she said in an Instagram story on Tuesday.
"But this page is to hold myself accountable."
The account is filled with before and after snaps of the 36-year-old, who owes her transformation to the "life-changing" surgery.
"I am finally enjoying my life without any physical limits. On vacation I always felt like the one that held the group back from things cause I couldn't walk that far or I would just sit out some activities. Not this time. I'm loving my life."
In July last year, Kayla shared her typical day on a plate, which includes a protein shake for breakfast, a chicken or beef dish with cheese for lunch and another protein for dinner. In between she opts for nuts including cashews or walnuts.
"So that's what I eat in a day. About 90g of protein, around 11g of carbs and about 5g of sugar … and just lots of water. I do that every day," she said.
