Dr Peter Brukner's "eureka" moment came at a time when his days were spent on the tense sidelines of English Premier League games, scanning the field for signs of player injuries and any niggles as the head of sports medicine for Liverpool FC.
It was 2012, and if you had asked Dr Brukner OAM how he was going, he would have said he was "pretty good".
But - then aged 60 - the Melbourne doctor and Professor of Sports Medicine at La Trobe University had noticed he was getting a little thick around the middle, despite his best efforts to stay trim.
"The kids were starting to poke me in the guts and say, 'Come on Dad'," Dr Brukner said.
"I'd just shrug my shoulders. I was eating a good, sensible, low-fat diet like I was supposed to do, and exercising regularly. I was functioning fine. I was OK. But the reality was that I probably wasn't quite as healthy as I might have let on."
At the time, the globally-recognised Australian sports physician had a fatty liver, high triglyceride levels, and high insulin levels.
"I was metabolically unwell, and in retrospect, clearly pre-diabetic," he recalled. "I was overweight - borderline obese, and like many middle-aged men, I had probably put on half a kilogram a year for 30 years."
Dr Brukner had a family history of type 2 diabetes. He had seen what the chronic disease had done to his late father.
"I was pretty keen not to go down that track, and that was always in the back of my mind," he said.
Dr Brukner has worked as a sports physician for the Australian cricket team, Collingwood and Melbourne AFL clubs, the Socceroos, and the Australian athletics team during the Atlanta and Sydney Olympics.
Looking after injuries, and helping athletes prevent new ones, was a big part of his role. Then there was nutrition advice, psychology support and general medical help when the teams were competing away from home.
His athletes had a lot to lose. Money. Prestige. Opportunities. Career-ending injuries were perhaps their greatest, most significant threat.
The pressure to make the right call for each of them, quickly and in front of millions of people watching around the world, was immense.
And it was all on Dr Brukner.
It was during his time at Liverpool FC that he decided to make a quick - potentially radical - call on his own health.
Dr Brukner had literally written the book on Australian sports nutrition - co-authoring Food For Sport in 1986. But as time moved on, he found sports nutrition was becoming a "bit dull".
It was essentially focused on carbohydrate and pasta parties the night before a marathon, washed down with Powerade and Gatorade during the games.
But it was stepping outside his comfort zone to dip his toe into a different way of eating that would switch his thinking "180 degrees". First for himself. Then others.
It was a personal experiment that would lead him to write the book, A Fat Lot of Good, and then put his name and reputation on the line to back Defeat Diabetes - an app that aims to help people improve their blood sugar levels through diet.
"A colleague in South Africa Tim Noakes - a very smart guy - had previously challenged accepted ideas and had been proven right," Dr Brukner said.
"So when he came out around that time and said he thought we'd been wrong about nutrition - that it was actually carbohydrates that were the problem, not fat, I remember thinking - 'Oh Tim, that can't be right'. The whole world couldn't have been wrong about nutrition for 30, 40 years.
"But he inspired me to do a bit of reading. I started with Good Calories, Bad Calories by Gary Taubes, and I guess you could say that book changed my life."
Dr Brukner explained the book had addressed the fats versus carbohydrates argument, and how the politics of the low-fat movement had "won out" over the low-carb, low-sugar regime in the 1960s and '70s.
"Which I'd always assumed was on the basis of good science, good evidence," Dr Brukner said. "But in reality it was on the basis of money and politics."
We had all spent the past few decades trimming the fat off our meat and eating low-fat dairy, when there was a good argument that it was the "worst thing we could have done," because the food industry had simply replaced the fat with sugar.
"I found it really disturbing. I put that book down and thought that it just couldn't be right," he said. "It blew me away, and I needed to find out more. I dived into every book and research paper and article I could find, and the more I read the more I was convinced we'd gotten it wrong. That it was actually carbs and sugars and starches that have been the problem, not fat.
"We have had the low-fat, high sugar diet for 30, 40 years, yet we have just gotten fatter and sicker ever since."
He decided he had nothing to lose but some excess weight, so he ran a little experiment on himself. He started and ended with blood tests. He checked his weight weekly.
"I stopped eating all sugars and starches - like rice, pasta, potato and bread - and I went back to eating the way my parents and grandparents had eaten - meat and fish and eggs and dairy, fruit and veg and nuts. No processed food. Just good, old-fashioned, sensible food," Dr Brukner said.
"I decided to do it for three months - or 13 weeks. The first thing that happened was that I stopped feeling hungry. Instead of getting up in the morning and having cereal for breakfast at 8am just to be starving again by 10.30, I'd have eggs and bacon and avocado - and I wouldn't be hungry all day.
"I went from eating three meals and three snacks a day to eating two meals a day - and I still eat two meals a day now."
He said as the weight started coming off, he began to feel more energetic.
"My sleep improved. My exercise improved. I could concentrate better. I just felt better and better over those three months. At the end of it, I'd lost 13 kilograms in 13 weeks. Without even trying. I was never hungry, I ate as much as I wanted to eat, and it was too easy.
"It was a breeze, and I enjoyed every meal I had.
"Carbohydrates make you hungry. They shoot your blood glucose up, and you pump out a whole lot on insulin, and then your blood glucose drops right down again. So two or three hours later, you're hungry again. That's why you're constantly snacking.
"Fats and proteins make you feel full."
He said the fatty liver he'd had for a decade, as well as his triglyceride levels, all came back to "normal" within those three months. And he felt great.
"The only downside was that I'd gone down a size and had to buy a new wardrobe," he said. "I figured that was a small price to pay. But it confirmed to me that we had been on the wrong track. That if I could reverse all my issues in three months, surely other people could too."
He had felt "obliged" to share what he had learned.
"I'm not suggesting I discovered it - at all - but when you come across something like this, you want to spread the word and tell people," he said.
Dr Brukner began speaking at conferences, and writing about his experiences.
He founded a not-for-profit organisation called "SugarByHalf".
"Sugar is the one thing everyone agrees on - even the dietitians agree on sugar - so we developed a campaign encouraging people to reduce the amount of sugar they consume by half," he said.
"That has been going for a few years now - in schools and via a good corporate program."
Penguin approached him to write A Fat Lot of Good.
"Clearly, what we are doing now is not working. We are getting fatter and sicker and have been every year for the past 30 or 40 years," he said.
"If you were running a business, and your bottom line was getting worse every year for 40 years, surely at some stage you would say 'Hang on a minute, maybe we are doing something wrong? Maybe we need to rethink things?' But no. We keep on doing the same thing, following the same diet, the same advice, and we have the same issues - only they just get worse and worse.
"It doesn't make any sense. We can't just accept that we are going to get sicker and fatter every year forever."
Dr Brukner said the "elephant in the room" was type 2 diabetes.
"It is a massive health issue in this country - and every western country. It is probably the biggest single health issue," he said.
"Traditionally, type 2 diabetes was regarded as a chronic progressive disease with no cure, no way of treating it other than medication. And its complications include kidney disease, eyesight problems, cardiovascular disease, amputations, dementia.
"But over time there has been some pretty good evidence, internationally, that treating type 2 diabetes with a low carb diet can be very effective."
Dr Brukner had considered licensing one of the digital diabetes programs that had already garnered positive results in the UK and the US to help tackle the problem in Australia.
Instead, about 18 months ago, he assembled a core group of doctors and dietitians - backed by a panel of various medical specialists including cardiologists, public health experts, orthopaedic surgeons and gastroenterologists - to develop Defeat Diabetes.
It launched in January with hours of videos, articles, meal plans, recipes and cooking demonstrations offered by fellow sports physician, Dr Paul Mason, and accredited practising dietitian, Nicole Moore.
Dr Brukner said a simple survey of the app's initial cohort of subscribers showed that after three months, 62 per cent had put their diabetes into remission.
"Which, according to the medical profession, you couldn't do," he said. "Yet here we are showing that it can be done, that people have been able to reduce their medication or go off their insulin and get a whole lot better."
But their claims that low-carb diets can help put type 2 diabetes into remission have been met with some resistance.
Diabetes Australia has only recently released a statement defining what it accepts as "remission". The latest national diabetes strategy also conceded that remission of type 2 diabetes in adults could be achieved with dietary interventions such as "stepped food reintroduction" and low carbohydrate diets - as well as bariatric surgery. But the strategy says that more evidence is still needed to establish the longer-term effects of dietary-induced diabetes remission.
"The medical profession would rather chop out half your stomach as a means of losing weight than ... get you to quit carbs," Dr Brukner said. "But it is what we are taught, it is what we know, it is what we're good at, and it is very profitable."
Critics have argued that low-carb diets can rob people of much-needed fibre to prevent inflammation and bowel cancer, that they can lead to a rise in LDL or "bad" cholesterol levels, and that the diet is unsustainable.
Dr Brukner disagrees.
"A lot of people want to find fault with it. And I get that. If I'd been advocating a certain diet for 30 or 40 years - which I had been - it's not easy to turn around and say, 'I might have been wrong'. No one likes to admit that," he said.
"I found it very difficult to come to terms with the fact I'd been giving the wrong advice. But ultimately, the evidence was so overwhelming that I had to take a deep breath and admit I was wrong. Science is always evolving."
Dr Brukner conceded some people had a "small rise" in LDL cholesterol, but that it was "more than compensated" by improvements in their HDL cholesterol and triglycerides.
"Which are probably even more important," he said. "Overall it has a positive effect. You can still have plenty of fibre on a low-carb diet, and I would argue that the results you get on a low-carb diet, and the way it makes you feel, is motivating enough to stay on it."
The pharmaceutical industry and food industry are both immensely powerful in our society. They have a lot of influence on the medical profession, politics and government, and they don't want things to change. We have to counter that.- Dr Peter Brukner
Dr Brukner said his team is embarking on some "proper research" on the efficacy of the Defeat Diabetes program through La Trobe University next year.
"We know it works. And we want to show that it works," he said. "We are doing that next year as the initial survey we did on our first cohort was just via email - so it's not counted as scientific research. But what it has done is given us an indication of whether we are on the right track.
"Sometimes I feel like I might be bashing my head against a brick wall with this stuff - then I'll get an email from someone saying 'You've changed my life' and it makes me realise it really is worthwhile."
But Dr Brukner said the "diabetes world" was slowly coming around.
Peak bodies globally were beginning to acknowledge that a low-carb diet was an "acceptable" approach in diabetes management.
"They are not saying it is the best yet. But, small steps. A few years ago they were all negative about it," he said.
"The pharmaceutical industry and food industry are both immensely powerful in our society. They have a lot of influence on the medical profession, politics and government, and they don't want things to change. We have to counter that.
"They have many millions of dollars to market and lobby. That's what we're up against.
"It's the tobacco debate all over again. We knew tobacco was harmful, yet the tobacco industry managed to delay and delay and delay and it took 30, 40 years until something was done. The same thing is happening with sugar and processed food. It is a disaster. We are getting fatter and sicker. Two thirds of Australians are overweight or obese. A quarter of our kids are overweight or obese. It is tragic.
"And we know that diet is at the heart of it."
Sign up for our newsletter to stay up to date.