The presenter, 58, has shed almost five stone after becoming unhappy with the way he looked and revealed the catalyst for his transformation came after seeing a picture of himself.
He told The Mirror: “There was a picture of me and John in India, my belly was coming over my trousers, and this big puffy face. For lots of overweight people it’s often a photo. They think, ‘Is that me?’ That was my moment.”
Wallace, who has launched a fitness platform ShowMe.Fit, said he was warned by his doctor to consider a change in lifestyle, citing “really high cholesterol”.
He said: “My life was the same as many people’s – lots of grazing, no proper meals and lots of takeaways. I was watching myself getting fatter and fatter and getting more unhappy about how I looked.
“I had really high cholesterol, too. My doctor told me I needed to do something because I was heading for a coronary.”
The BBC star recently revealed he was motivated to lose weight to “look better” on TV and said his new found confidence has helped his marriage to Anne-Marie, with whom who he tied the knot in 2016.
He told The Sun: “My motivation at the start was, ‘I just want to look better on the telly’. But now it’s, ‘How fit can I actually get? Can I actually have the body of a 20-year-old at 60?’.”
“I feel more attractive, I’m nicer to be around and, let’s be honest, my wife Anna is 22 years younger than me and while I can’t change my age, at least I can change what I look like.”
The TV personality, who is 5ft 8in and weighed 16st 7lb at his heaviest, said he tried to lose weight quickly but felt “hungry and miserable” all the time when he tried fad diets.
Wallace managed to lose almost five stone by weaning himself off fast food, exercising and cooking healthy meals at home.