Now she encourages others on social media to take control of their diet and exercise regimes, pointing out that it's as easy as changing your mindset.
Belinda posted a photo to show what she looked like at 27, and now at 43, to show how much has changed.
'The most important change is my confidence in my body and mind. I am getting up every day happy, energised, vibrant, going to the bathroom daily (to do number two) regularly and my mobility (zero pain from back/hip/knee or skin issues from eczema),' Belinda wrote on her website.
When it comes to what she has changed, Belinda said the only things she has done is eat quality food with no preservatives and walk or run for 30 minutes every single morning.
The PE teacher said she makes sure she completes four weighted training sessions a week, and thinks about her posture in every day movements so she isn't slouching when she's stat down.
Lastly, Belinda said she only thinks positively about her own ability and doesn't let negative thoughts into her head.
'Dedicate to being healthy every single day; doing the best for your body. No cheats, no easy pathway,' Belinda said.
'The only thing different about me from then to now is my health and happiness. Yes, I've got blonder hair; yes I am standing strong; yes I lost some kilograms and reshaped my body.
'But the key fact is: I'm the healthiest I've ever been from the inside out. Why? Because I chose to find my best health in the right food for me and the right fitness. It is not magic, it is not Photoshop, it's just me.'
While the mum said she was guilty of 'making excuses' around food and exercise when she first became a mother, she also said a comment from her then-husband prompted her to get her body back on track.
When he showed her a photo of a toned woman, she said she wished she could look like that and he told her no matter what she did, she never could look like that.
'That was the sentence that lit a fire in my belly,' Belinda told FEMAIL.
What were the steps Belinda took to lose the weight?
Step one: Set a food regime.
Step two: Correct your fitness.
Step three: Get consistent and goal-focused.
Step four: Include personal rewards, such as a facial or a massage - not chocolate.
'Doubters have always spurred me on.'
And so, the full-time physical education teacher used her knowledge of sports and nutrition to develop a way of eating and exercising that fit into her schedule as a busy mum.
'The steps I followed were pretty straightforward,' the author of Fit Mama said.
'Step 1: I set a food regime. Step 2: I corrected my fitness. Step 3: I was consistent and goal-focused. And Step 4: I included personal rewards, such as a facial or a massage - not chocolate.'
Belinda said that 'being truthful' with herself was hard at first, but gradually over the course of a year, her body started changing shape.
'Within 20 weeks of eating healthily and exercising three or four times a week, people noticed differences in my skin, energy and mood,' she said.
What are the foods Belinda eats?
Oats
Blueberries
Almond milk
Coffee
Bananas
Chicken
Salmon
Salad
Broccoli
Eggs
Spinach
Beetroot
Sweet potatoes
Pumpkin
Quinoa
'Then, the body changes came too.'
She slowly and steadily moved from 80 kilos to her current weight of 62 kilos.
The 43-year-old said food is the key to being in good shape in your 30s and 40s.
'Focus on how often you eat, how much you eat and then simplify the eating and preparation process,' she said.
'Processed meats should never pass your lips as they are poison to the body.
'While they are marketed as high in protein and healthy, I totally disagree and have seen dramatic health changes in myself and other women who avoid them altogether.'
'I live entirely on oats, blueberries, almond milk, coffee, bananas, chicken, salmon, salad, broccoli, eggs, spinach, beetroot, sweet potatoes, pumpkin, quinoa and peanut butter,' she said.
Instead, Belinda focuses on nourishing her body with plenty of lean protein and green leafy vegetables.
