A crash diet lasting just eight weeks can reverse type 2 diabetes, experts have found.
Even people who had suffered with diabetes for a decade saw their condition eradicated after they restricted their eating for two months.
And six months after stopping the diet, participants in the Newcastle University trial were still free of the disease, suggesting that the condition had effectively been reversed.
The findings described last night as a "paradigm shift" in the understanding of diabetes could lead to a cheap way of dealing with the problem that affects 3.6million people in Britain. More than 257, 000 New Zealanders live with the disease.
Type 2 diabetes occurs either when the body does not produce enough insulin to control the blood sugar ñ or the cells donít react to it. The condition is often linked to obesity and usually occurs in middle age, coming with a risk of limb amputations, heart attacks and vision loss.
Experts used to think that once the disease had taken hold, it was incurable. But a growing body of evidence suggests that losing weight could reverse the condition. Scientists think that this is because removing fat from the pancreas allows insulin production to return to normal, eradicating the problem at the root of the disease.
Now, a British trial has suggested that the condition could not only be reversible but that the reverse could come in a matter of weeks.
Study leader Professor Roy Taylor said: "The bottom line is that if a person really wants to get rid of their type 2 diabetes, they can lose weight, keep it off and return to normal."
In his trial, diabetics who ate just 700 calories a day made up of three diet shakes a day and some vegetables ñ lost an average of two stone (14kg) in eight weeks. Of the 30 participants, 12 saw their diabetes reversed.
The participants then gradually increased their eating to healthy levels, a third less on average than they ate before the trial. When they were reassessed six months later, none of the participants had put back the weight, and none of those whose diabetes had been reversed had seen the diabetes return.
Though the volunteers remained overweight, they had lost enough weight to remove the fat from the pancreas and allow normal insulin production to resume.
The authors, writing in the Diabetes Care medical journal, said: "Type 2 diabetes has reached epidemic proportions. The personal cost is enormous in terms of visual loss, amputation, and premature cardiovascular disease.
"The inevitably progressive nature of the disease has appeared beyond question. At diagnosis, patients are advised to accept having a lifelong disease."
But they said their results showed that this approach had been incorrect. "Type 2 diabetes can now be understood to be a metabolic syndrome potentially reversible by substantial weight loss, and this is an important paradigm shift."
Professor Taylor said: "What we have shown is that it is possible to reverse your diabetes, even if you have had the condition for a long time, up to around ten years. If you have had the diagnosis for longer than that, don't give up hope ñ major improvement in blood sugar control is possible.
"The study also answered the question people often ask me 'if I lose the weight and keep the weight off, will I stay free of diabetes?' The simple answer is yes!
"Interestingly, even though all our volunteers remained obese or overweight, the fat did not drift back to clog up the pancreas."
His team thinks that each person has a "personal fat threshold" and if they surpass this their body can no longer properly regulate blood sugar levels. The professor said: "If a person gains more weight than they personally can tolerate, then diabetes is triggered, but if they then lose that amount of weight then they go back to normal.
"Individuals vary in how much weight they can carry without it seeming to affect their metabolism - 70 per cent of severely obese people do not have diabetes."
The team has already started a larger trial involving 280 patients to see if the results can be replicated. That trial, which reports back in 2018, will examine whether dieting can reverse type 2 diabetes in all patients, or if only certain people respond.
The number of people with diabetes has soared by two-thirds in the last decade, fuelled by Britain's obesity epidemic. Last year the number topped 4million for the first time. Nine out of ten have type 2. The rest have the genetic form, type 1, an irreversible auto-immune disease which is nothing to do with lifestyle.
"I lost 2st and now eat normally. It's changed my life"
In just two months Allan Tutty's life changed. A crash diet lasting eight weeks slashed two and a half stone from his frame and reversed his type 2 diabetes.
The father of four had never felt fat, but scans showed a layer of blubber around his internal organs. Mr Tutty, 57, from Sunderland in the UK, said: "I was diagnosed with type 2 diabetes around May 2011 during routine checks by my GP. While I didn't feel fat, I was fat - on the inside. I've seen a scan of my liver and you can see the fat around it."
Mr Tutty, who manages a brain injury unit at a care home and weighed more than 95 kilograms before the diet, added: "I took part in the Newcastle University research, spending eight weeks on a very low calorie diet which was really tough over Christmas and New Year but I was determined to complete it.
"In the two months, I lost two and a half stone and my pancreas was working within normal limits. With my diabetes in remission, I haven't looked back. I eat normal foods, though I eat less than I used to, and I enjoy takeaways and chocolate but not on a regular basis so I have maintained my lower weight. My life has changed completely thanks to this research."
- Daily Mail