Brooke said that while she couldn't believe how different she looked, it was also how she felt that prompted her transformation.
The mum said she would struggle doing "simple" things such as sitting down on the ground or pushing her kids in the pram, often feeling "heavy, exhausted and lethargic".
"Because I enjoyed being a mum so much, I wanted to make changes to keep up with them," she said.
The mother of two said while she had a mostly healthy diet, it was her snacking and portion sizes that would let her down.
"Even though my main meals were healthy, I ate whatever I wanted when I wanted and after I stopped breastfeeding, I didn't change the way I was eating."
So in July 2019 the South Australian mum embarked on a journey that would ultimately see her lose 25kg in 25 months.
"I started small and did what was achievable for me to give me a sense of accomplishment and motivation," Brooke said.
"I made sure I gave myself time to do some form of exercise and began with taking the kids for a walk in the pram. It was very simple but that's all I could manage."
She also joined The Healthy Mummy, using the programme to help manage her snacking and educate her around portion control.
"Using their app and Facebook page has really helped me learn about healthy choices to replace unhealthy food with, the importance of tracking and falling in love with exercise and how it makes me feel better."
Brooke, who's boys were 2-and-a-half years old and 10 months at the time, went on to increase her walking distance to 4km while also pushing the pram up and down hills.
She now runs for 5km most days while also adding at-home equipment-free workouts.
"I once struggled to do one push-up on my knees. Now I can do 25 full push-ups and I can also keep up with my boys [now aged 4 and 2]."
Brooke said to be active with her kids was one of the biggest motivators behind her transformation, adding she feels stronger than ever.
"It's about helping them have a fun life. I remember doing things like going on bushwalks with my family and now I can create those memories with my own kids."
But like any change, Brooke said it came with its own set of challenges. For her, she realised one of her biggest problems was "emotional eating".
"I had to really retrain my brain," she said. "It takes time and persistence.
"I haven't been perfect, but I have been persistent and not given up."
Brooke said she feels 100 per cent more confident, both physically and mentally.
"I am in the best mental space I have been since becoming a mum four years ago," she said.