It was a normal day in 2012 when Dr Michael Mosley made an appointment with his doctor.

The British television producer and presenter was worried about a possible melanoma on his skin that had been playing on his mind.

He rolled up his sleeve for a blood test before being sent away, left to wait for the results.

"Good news, your skin is fine," his doctor told him.

The diagnosis would be the catalyst for a health journey that would bring Dr Mosley worldwide recognition, influencing the eating habits of millions and drawing criticism from other medical professionals.

Popularising intermittent fasting

Following his diabetes diagnosis, medication was instantly mentioned as the logical next step.

But Dr Mosley said, "no thanks".

"My dad had had type 2 diabetes and had died of complications, even though he was taking the medication," he said in an interview with The House of Wellness in 2020.

"So I thought, this is not a good way to go."

Dr Mosley had previously heard about intermittent fasting and immediately started researching.

His research led him to get in touch with neuroscientist Mark Mattson, who published a paper on the 5:2 diet with 15 other scientists the previous year.

The 5:2 diet is a type of intermittent fasting where calories are restricted for two days of the week, with normal calorie intake for the other five days of the week.

At this point, Dr Mosley had been working with the BBC for decades and had presented and produced a number of science programs.

He couldn't deny his diagnosis would make compelling viewing.

"I persuaded the editor of [BBC science program] Horizon … to commission a film to see if I could cure myself of diabetes through intermittent fasting," he said.

Dr Mosley had no inkling his experiment would work, but remained optimistic.

At the end of the program, Dr Mosley had lost 9kg and his blood sugars were "entirely fine."

The episode drew a surprisingly high audience of 3 million viewers, particularly as it aired during the London Olympics.

"I was absolutely astonished, I have to say," Dr Mosley said on reflection once the experiment was complete.

Diabetes 'in remission'

Dr Mosley has said, "at each stage, I've relied on other people's science".

In order to understand what just happened to his body, Dr Mosley got in touch with Professor Roy Taylor at Newcastle University.

"He said, basically it was a rapid weight loss that had led to the fat draining out of my liver and my pancreas," he said.

Dr Mosley said Professor Taylor had already demonstrated in a dozen patients that you could "put diabetes into remission".

"That's the word he uses. He doesn't like the word 'reverse' because reverse implies it's permanent and if you put the fat on again, then there's a good chance it will come back.

"He's the guy who explained the science to me, he had all the science behind him, he was one of the world's leading diabetes specialists … and no one believed him. All the other doctors said this was nonsense.

"He said, 'I'm seeing all these patients who are losing weight, their diabetes is going away — explain that.'"

The bestseller and the 'fasting frenzy'

Soon thereafter, Dr Mosley paired up with food and fashion writer Mimi Spencer to write The Fast Diet.

The book became a bestseller in the UK, with the New York Times saying Dr Mosley had "sent the British into a fasting frenzy."

Celebrity chef Hugh Fearnley-Whittingstall wrote in The Guardian that he felt "lean and sharp" on the diet, adding "I feel I might just be part of a health revolution".

But the book's success was not without its criticism.

Shortly after its publication, Britain's publicly funded National Health Service (NHS) put out a statement on its website.

"Despite its increasing popularity, there is a great deal of uncertainty about IF [intermittent fasting] with significant gaps in the evidence."

And while scientists had done plenty of research on the benefits of intermittent fasting on rats, there weren't many trials done on humans.

According to Diabetes Australia, intermittent fasting can be safely undertaken by someone with diabetes, but there are some considerations, including first speaking with your doctor beforehand.

Years later, in 2021, Dr Mosley would present a Channel 4 series called Lose a Stone in 21 Days.

The program claimed individuals could drop 1 stone (6.4kg) in 21 days by calorie restricting to 800 calories a day.

Beat, a UK charity supporting those affected by eating disorders, wrote that "the programme caused enough stress and anxiety to our beneficiaries that we extended our Helpline hours to support anyone affected and received 51 per cent more contact during that time".

From medicine to television

Born in Calcutta, India, Dr Mosley moved to England with his family when he was a child.

He studied philosophy at Oxford University before later moving into medicine with the intention to become a psychiatrist.

But in 1985, a disillusioned Dr Mosley joined a trainee assistant producer scheme at the BBC.

He has produced a number of programs, including the 2004 series Inventions That Changed The World with then Top Gear presenter Jeremy Clarkson.

His influence also spans to Australia.

In 2021, he presented the series Australia's Health Revolution for SBS, which was followed by Australia's Sleep Revolution three years later.