Worthing student Charlotte Randall joined other successful slimmers at Westminster to help raise awareness of the support available for people living with obesity.
Charlotte, who was named national Young Slimmer of the Year 2018 by Slimming World after losing 4st 10lbs, was a special guest at the parliamentary reception, hosted by Baroness Floella Benjamin.
She said: "I was honoured to be asked by Slimming World to join them at Westminster and was very happy to talk to reception guests, including MPs and health professionals, about how joining Slimming World and losing weight has changed my life.
"I really hope that sharing my personal experiences will give them a better understanding of how overweight people feel and what a difference getting the right tools, like a flexible and generous healthy eating plan and encouragement to become more active, and support can be."
Charlotte has gone from a clothes size 18/20 to a size 10/12, having dropped from 15st 10lbs to 11st in weight.
"I never could have dreamed that I'd be in this position when I first began my weight-loss journey,” she said.
Andrew Selous MP, co-chairman of the all party group on obesity and member of the health select committee, spoke at the reception. He was joined on the platform by Charlotte and other Slimming World members, who shared their personal weight-loss stories.
Charlotte, who is 5ft 10in tall, had always dreamed of studying performing arts at university but as she was nearly 16st, she feared she would spend her life confined to 'big girl' roles.
She said her weight held her back a lot, as she was always the shy one hiding at the back in baggy clothes and she never put herself forward for roles.
She was always the biggest and tallest in her class throughout primary and secondary school but it did not worry her until her teenage years, when she gained 4st 7lbs in 12 months after meeting her partner of two years.
Charlotte suffered numerous embarrassing incidents, including her trousers ripping in public and being given a seatbelt extension on a rollercoaster at Thorpe Park because she was too big for the normal belt.
Her mum was a member of Slimming World and she encouraged Charlotte to join her after her daughter, who had just booked a foreign holiday, spoke of her worries about feeling uncomfortable on the beach.
Charlotte says her confidence has grown immeasurably since she had lost weight and she is ready to take centre stage. She attends extra dance lessons outside college and has even taken part in a dance competition.
The parliamentary reception was part of a day of action, in which MPs, peers, health professionals and other industry experts debated ways to tackle the obesity epidemic.