Eventually, her excess weight meant she was struggling.
"The changing point," her mum said in the video, as Melanie began her meal plan - which included eating more veggies and less high-fat foods.
Each week, Marla would upload a new video to document the journey, with photos showing a grinning Melanie who was clearly proud of her progress.
At an update at the 18 week mark, mum Marla said: "She was off the chart on the BMI for kids chart. I'm so proud of her." Alongside a photo showing a happier child and the visible change to Melanie's figure.
In the photos, Melanie's smiles get bigger as her tummy gets noticeably smaller.
Then, after just over four months, Melanie took to the scales again to find out her final weight.
She was 31 kilos, which was a remarkable drop of 12 kilos.
As an ecstatic Melanie danced happily, "Way healthier baby," said her mum.
Less carbs and more cardio can help with weight loss. And during her 20 week transformation, Melanie ditched the junk food and used healthy eating as well an exercise plan, which included roller skating, trampolining and swimming - as well as playing outside - in her mission to lose the extra weight.
"Thanks for the motivation," they posted at the end of the video, which has since gone viral on Facebook.
