Guzzling more than 100 pints of coke a week, Graham Waugh weighed 52 stone and was dubbed one of Britain’s fattest men.
But after shedding more than half his body weight, he now plans to help others do the same by opening the UK’s first gym for the super obese.
The father-of-two, of of Luton, Bedfordshire, piled on the pounds when mental health issues trapped him indoors for more than a decade.
Mr Waugh, 45, ate 12 takeaways and 21 family bags of peanut M&Ms over the space of a week before washing it down with a can of coke every half hour while suffering from depression and anxiety.
The now married man also used to smoke 80 cigarettes a day but when his brother died he decided it was time to turn his life around.
He lost 31 stone thanks to a rigorous gym routine, strict diet and two operations and the achievement thought to be one of Britain’s biggest weight losses.
He said: “All I could concentrate on was food. I felt like I had nothing else in my life.
“I would eat lunch and instantly think that was for dinner.
“I felt as if I was on death row – I know how these people feel – but now I got lucky and it worked out.
“It hasn’t been easy but I feel like a totally different man.
“I was expecting to be dead by now. I feel like I have cheated death without a doubt.”
Mr Waugh had always been larger than his peers and would get in trouble at school when he would try to make people laugh to avoid being bullied.
His weight first spiralled out of control when he suffered from heart palpitations aged 27 – weighing 27 stone – which caused him to panic and become a recluse.