LEE McAllister used to sweat and fret about making the weight. So the first sign that his heavyweight match-up against Danny Williams at Aberdeen’s beach ballroom a fortnight ago would be a fight with a difference came with a glimpse of his pre-weigh in diet. “I had a baked potato, two bottles of water, a diet coke and a sticky toffee pudding before I even weighed in,” McAllister says.

Even in the seamy old world of boxing, the McAllister story takes some re-telling. The WBU belt he ended up with, a version of the heavyweight championship of the world, meant he had won titles at four different weight classes. Starting out life as a lightweight at a mere 9st 9oz, he had stepped up fully seven categories, weighing in just two pounds over the lower limit for heavyweight contests at 14st 7oz.

Not only was his opponent Williams a two-time British heavyweight champion who stopped Mike Tyson in 2004 and had gone toe-to-toe with Vitali Klitschko, Dereck Chisora and Audley Harrison, he weighed in for the fight at 18st 10oz. Or to put it another way, roughly double McAllister’s original body weight. It is a bit like Josh Taylor deciding to pass on the light welterweight World Super Series to take on Anthony Joshua instead.

No wonder the place went mad when McAllister, ten years the younger man, dropped his 45-year-old opponent three times before his corner finally towel threw in the towel during the tenth round. A title winner at welterweight as recently as last year, who had only taken the opportunity to move up to heavyweight in April as a late replacement to defeat Lee Kellet, McAllister admitted his crash diet had utterly sickened him to food.

“It was very hard preparing for the fight, because as soon as I did any running or any cardio work at all, the weight would start to drop off again,” says McAllister. “I had to train during the day then eat at night when I got home, something like a pizza, just to try to keep the weight on.

“I was sick to death of eating by the end of it – I had to go on a diet,” he added. “I was probably eating about 5,000 or 6,000 calories a day, I would eat properly during the day then when I got home at 8 at night I would be eating anything – pizza, Chinese or Indian - just to get the weight back on.”

Was it worth it? Well, while McAllister feels sure his days as heavyweight are gone, at least he has quite a claim to fame. “It was always an ambition of mine to be heavyweight champion of world,” he said. “Everyone always dreams about that, don’t they, as a kid, ever since watching Rocky. I always thought I would try it, and last year was the time. I just thought I would beef up, bulk up and give it a go.

“All my family have always been quite large set, quite stocky,” he added. “I’ve done my best over the years to try to make myself skinny but I’ve always struggled to keep my weight down. I always thought that boiled down to giving me some sort of advantage.

“The biggest crowd I ever fought in front of was Braehead Arena, on a Scott Harrison undercard, but was it the best moment of my fight career? I would say so. Beating a fight legend like Danny is a massive scalp for me, especially with him coming off three first round knock downs.

“As much as everyone was like ‘look at the size of that guy’, you can’t catch what you can’t hit, if you know what I mean. I have managed to keep the speed of my feet even though I have gone up the divisions, that is quite a shock, because I thought I was going to lose it. And my hand speed.

“You could have cut the atmosphere on the night with a knife, honestly. A lot of people there were actually worried for my safety. But when I dropped him and he hit the canvas everyone just went f**king mental.”

So what happens now? It is a good question. Without the backing of one of the major promoters – McAllister essentially promotes himself now – it is unclear how much he will be able to cash in on this new-found fame. He will decide in the next few weeks who his next opponent will be. And what weight class. But it won’t be heavyweight. “I don’t know 100% yet but possibly it will be around December time,” said McAllister.

McAllister has proved plenty, not least about what the human body can withstand. But he also proved how much he loves the sport. “A lot of people drag themselves out of bed in the morning or put themselves through training because they need money to pay the mortgage or whatever,” he says. “But I don’t do it for the money. I do it because I love it. I am either mad or very brave. Or a bit of both.”