The Olympic swimming champion, who gained 25kg while pregnant with son Jacob in 1998, has spoken out about her own weight battle and low self-esteem.
Lewis told the Herald Sun: "I’ve watched The Biggest Loser since the first season and to see what these contestants overcome is so inspiring. I can empathise with them because I’ve been in their shoes and know how low you can feel. I can't wait to start this hosting job."
The 35-year-old sports star said about her weight issues: "There were times I didn’t want to get out of bed or put on my togs because I was too embarrassed...a glossy magazine came out and said I wasn’t your typical athlete and a little bit heavy legged."
She added: "It was really hard. I was only a young girl and I had to wear togs every day of my life, you can’t hide. I was embarrassed and upset. It’s tough and more problems came when I had children."
Lewis is replacing former host Ajay Rochester, who was rumoured to have been axed from the show after hitting headlines for her welfare fraud court case.