The most common form of diabetes can be reversed by nothing more than a severe low-calorie diet, a study has found.
Type 2 diabetes, which affects around 3.5 million people in the UK and costs the NHS an estimated £9bn a year, is caused by high levels of glucose in the blood and is linked to overeating and obesity.
Researchers say the "remarkable" discovery proves that a simple eight-week diet can do away with the need for years of expensive medication.
Professor Roy Taylor, of Newcastle University, who led the study, said: "For many years, it has been assumed that type 2 diabetes is a life sentence.
"It's chronic, it's progressive, people need more and more tablets, and eventually they need insulin. It's a downhill slope.
"However, we have been able to show that it is in fact reversible."
In the study, funded by the charity Diabetes UK , doctors selected 11 type 2 diabetics and used a powerful scanner to monitor fat in the pancreas which regulates blood sugar levels.
The patients were then put on a strict diet of just 600 calories a day consisting of slimming shakes, non-starchy vegetables, tea and zero-calorie drinks.
After just one week, early morning blood sugar levels had returned to normal among the group.
After two months the fat in the pancreas of each patient had returned to normal levels and the pancreas was making insulin normally.
Three months later, after going back to normal eating with advice on portion control and healthy foods, seven people remained free of diabetes.
"The insulin-producing cells in the pancreas have gone to sleep in type 2 diabetes - they are not really doing very much," explained Professor Taylor .
"As the level of fat in the pancreas has reduced, we have seen these insulin-producing cells come completely back to normal, and that is truly remarkable."
Retired lorry driver Gordon Parmley, from Stocksfield in Northumberland, spent four years on daily medication for type 2 diabetes despite being only 2st overweight.
The diet worked and 18 months later he is still free of diabetes and does not have to take any tablets.
"It was very tough. I was hungry all the time. It was a starvation diet and food was on your mind all the time," he said.
"At the end of the eight weeks when they said that my pancreas was working again and producing insulin and that I could come off all the tablets I was on for the diabetes then it was absolutely fantastic, it was like winning the lottery."
The researchers, who are publishing their findings in the Diabetologia medical journal, say anyone who wants to try the diet should consult their GP first.