How Lisa Wilkinson's groom Peter FitzSimons lost 46 kilos before their second wedding

Lisa Wilkinson has opened up about her husband Peter FitzSimons' health journey, which saw him shed 46 kilograms before they tied the knot for the second time over the weekend.

The 57-year-old TODAY host gushed about her hubby's transformation, and said that it began when they started working out together.  

"He’s kind of passed me by in the fitness department," Lisa told Yours magazine. "I was always secretly thinking, 'Well, at least I’m looking after myself better than my husband is!' But we started going to the gym together, and he gave up sugar and alcohol, and [that was when] everything came right for him."

She added, "I’m particularly happy for him because I can see he’s enjoying every day so much more."

Peter, a professional rugby union player-turned author, made headlines last year when he dropped almost a third of his body weight.  

"This is the key: stop the sugar, stop the hunger,” he told 60 Minutes host Liz Hayes in November. "When I stopped the sugar and I weighed myself, every day I was losing a quarter or a third of a kilo."

He also put his dramatic weight loss down to quitting the grog.

Almost a year later, and Peter's lifestyle change continues to have positive effects on the entire family. 

"I think that’s the real message of good health – you get a lot more out of the day, you sleep better, and I think you have better relationships as you don’t have the aches and pains that can come with getting older," Lisa told the publication.

The couple renewed their vows -- and marked 25 years of marriage -- at Sydney’s Balmoral Beach Bathers Pavilion on Saturday.   

The bridal party was made up of the couple's three children -- sons, Louis and Jake, and daughter, Billi.