Mallory Buettner, 29, from Quinte West, Ontario, Canada, underwent a gastric bypass two years ago after her weight reached almost 400lbs (28st), helping her to shrink to 187lbs (13st).
On June 30, to complete her transformation, Mallory had a tummy tuck and brachioplasty to remove 10lbs of loose skin from her stomach and arms.
Having never worn a bikini before, even in her own garden hot tub, the delighted teacher celebrated by purchasing five new two-pieces.
But the super slimmer paid a price for her new body including surgery complications, and having to call off a wedding to her ex-fiancé who she said struggled with her new life.
Now the brave brunette is opening up about 'life after going under the knife' to encourage other weight loss hopefuls to ask for help.
Mallory said: 'I had never worn a bikini in my life, and I had a dreaded putting on a bathing suit even in my own hot tub in the back yard.
'I live in a bikini now. I wear one every day, I am a bikini bum. After the surgery, I went out and bought five bikinis.
'For the first time I feel like the outside matches the inside.' 'At school I was the biggest kid in the class. I was aged eight-years-old the first time I went on a diet.
'My mum always made an effort to feed me lean meals but when I was little, but I liked to eat chips, pizza and pop.
'Then at I high school I drank a lot of ice coffees and ate McDonald's.' When nothing else worked, Mallory turned to the Doctor Bernstein Diet for help.
After years of failed diets, Mallory gave in to doctors' recommendation and following a consultation in November 2013, booked RNY surgery for the following May.
However, in a twist of fate, the newly engaged young-woman was forced to choose between her health and her husband-to-be.
She said: 'I was engaged at the time. The surgery was scheduled for two months before the wedding.
'He wasn't supportive and liked things the way they were. I think he thought I wouldn't love him after I lost weight.
'We called off the wedding days before the date and never spoke again. It was the hardest thing but I had to choose to be happy.
'We both moved on and I hope he is happy.'
Although surgery complications resulted in a hematoma which had to be removed, Mallory has finally be able to celebrate her new look, two months post-op.
She added: 'After surgery, I sent a bikini photo to my mum and my sister and they both said how proud they were.
'It has not been easy that's for sure. I now know that surgery is hard and recovery is much harder. I've made sacrifices and it is not the easy way out like I thought.'