Consuming 850 calories a day for three months and then keeping the weight off can arrest type-2 diabetes for at least two years, a study suggests.
The GP-led programme worked for more than a third of participating patients.
The study report builds on earlier work suggesting weight loss is one key solution and offers more time off medication than previously thought.
Experts say it challenges the view that type-2 diabetes is always a life-long, progressive condition.
Type-2 diabetes affects one in 16 adults in the UK.
It causes uncontrolled sugar levels that can lead to serious complications such as amputations, visual problems and heart disease.
‘I lost 17kg in 12 weeks’
Joe McSorley, 58, who lives near Glasgow, was diagnosed with type-2 diabetes six years ago and though he was given two types of medication, found it hard to keep his blood sugars under control.
He told BBC news: “All I could see for the future was continuing to take these pills forever.”
When he started the trial diet – consuming only low-calorie shakes every day – he found it very difficult.
But he saw rapid results, dropping from 90kg (14st 2lb) to 73kg in just 12 weeks.
And, Mr McSorley said, the hardest part came when he had begun to eat solid food again.
“Using the shakes is only the start of the journey,” he said.
“It gets you to the point where you can take destiny in your own hands.”
Two years later, his weight is stable at 77kg.
He exercises regularly and hopes to become a lifestyle coach when he retires.
Mr McSorley was one of 149 people in Scotland and Tyneside put on a 12-30-week low-calorie diet of shakes and drinks to help trigger weight loss.
They were then reintroduced to solid meals over the next few weeks.
After one year, 69 of them (46%) had gone into remission, compared with just 4% of people given standard treatment including pills.
And after two years, 53 of them (36%) remained off medication and in remission.
Participants were encouraged to keep healthy through monthly meetings and had the option of a “rescue” plan including using the liquid diet again, if they gained weight.
‘Not all about weight’
Prof Roy Taylor, an investigator on the trial, said: “These results are a significant development and finally pull down the curtain on the era of type-2 diabetes as an inevitably progressive disease.”
Researchers said most of the weight-loss group whose diabetes had gone into remission had lost 10kg or more and maintained this weight loss during the trial.
But Dr Nicola Guess, at King’s College London, said weight loss was not the whole story.
“Type-2 diabetes returned in a minority of people (16%) who kept off 15kg or more for two years,” she said.
“Further research is needed to help us understand why this is.
“It is possible that these people had type-2 diabetes for longer before losing weight or perhaps there might be dietary or genetic factors which contributed.”
The NHS is piloting the programme but cautions that this type of calorie restriction is not be suitable for everyone and should be done under medical supervision only.
The charity Diabetes UK, which funded the study, said the findings were exciting but added: “We know type-2 diabetes is a complex condition and this approach will not work for everyone.”
The trial is published in the Lancet Diabetes and Endocrinology.