SUNSHINE Coast mum Nikki has been with her partner for three years but he has never seen her naked.

That's how insecure she is about her body.

The full-time mum's story features on the latest promo for The Biggest Loser: Transformed, and began airing on Sunday.

Growing up on the Coast's beaches was a blessing and a curse for Nikki, 25, who is ashamed of her weight.

"I want to be able to get into my dream bikini and be able to wear whatever I want to wear and feel beautiful and comfortable," Nikki said.

The young mum is ready to swap her insecurities for self-love as she begins her life-changing journey on the reality TV show.

She joins fellow Coast contestant Lynton, who signed up for the weight loss challenge in order to save his career as a pilot, and 14 other contestants.

Helping them in their eight-week journey will be host Fiona Falkiner, a model and former Biggest Loser contestant, as well as two of Australia's leading trainers and fitness professionals, Shannan Ponton and Libby Babet.