Up to 100,000 people in the UK should be given weight-loss surgery in the hope of achieving remission from Type 2 diabetes, world experts have said.
A coalition of organisations - including Diabetes UK and the American Diabetes Association - said surgery is a cost-effective option for people with the condition and should be recognised as a standard treatment.
Publishing new guidelines, experts said the UK should be aiming to carry out up to 50,000 operations a year to bring it into line with other European countries, up from around 6,000 at the moment.
Evidence from 11 clinical trials shows about half of patients go into remission from diabetes that lasts at least five years following weight-loss surgery. This shows it is a "very powerful treatment", said Francesco Rubino, one of the experts behind the guidelines and professor of metabolic and bariatric surgery at King's College London.
Those who have the operation also experience far better blood sugar control than those who try to lose weight as a means of controlling their diabetes, he said.
Under the new guidelines, backed by organisations including the International Diabetes Federation and Diabetes India, anyone with Type 2 diabetes who has a body mass index (BMI) of 40 or more should be offered surgery regardless of their blood sugar levels.
Those with a BMI of 30 or over - the threshold for being clinically obese - should also have surgery as an option if their blood glucose levels are not well-controlled despite taking tablets, insulin or following weight-loss programmes.
Type 2 diabetes is strongly linked to unhealthy lifestyles, with obesity one of the main risk factors. Experts put the cost of each operation to the NHS at between £5,000 and £6,000.
Professor Sir George Alberti, co-author of the guidelines report, said: "We are changing the paradigm here, we are not talking about the treatment of obesity, we are talking about the treatment of diabetes."
He said "we have a pandemic on our hands", adding that there were now at least 422 million people with diabetes across the globe.
In the UK, around 3.5 million have diabetes, of whom around 500,000 do not know they have it, he said. This can lead to eye and nerve damage, kidney failure, amputations and heart attacks and strokes.
Prof Alberti added: "The more severe amongst my colleagues would say you just need to diet and exercise and it goes away... but getting people to sustain that for a long period of time is almost impossible."
He said it was "very easy to take a punitive approach".
He said: "People say 'it's all your own fault, just lose weight', but that doesn't help anybody. There are people who find it very, very difficult and are miserable as sin as a result."
He said around half of people with diabetes have blood sugar levels that are too high and are not well controlled, putting them at high risk of complications.
The UK is also way behind other countries in offering surgery, he added.
"If you consider that we've got... half a million severely overweight with diabetes, then we are just scratching around. It's getting through to our colleagues and the NHS that this (surgery) is a real treatment for diabetes."
He said the clinical trials showed that 30% to 50% had remission from diabetes for at least five years.
"If you can buy five years of normal blood glucose even if you remit afterwards, that is a five-year further delay in developing eye damage, kidney damage... so anything you gain is very much on the plus side."
Prof Rubino, first author of the guidelines report, said that when obese people go to their GP "they are likely to hear that surgery may be an option" but those who present with Type 2 diabetes will rarely hear about surgery.
"This is what we are trying to change," he said. "Surgery is a true diabetes intervention." He said it made "no medical sense" and "no economical sense" to continue patients on pills or insulin that was not working.
Prof Rubino said the guidelines had been endorsed by 46 professional scientific societies and the number would grow. "It's the largest endorsement in the field of diabetes and one of the largest endorsements for guidelines in medicine," he said.
Simon O'Neill, director of health intelligence at Diabetes UK, said: "We strongly support the call for obesity surgery to be fully recognised as an active treatment option for Type 2 diabetes alongside established forms of Type 2 diabetes treatments, such as lifestyle changes, and blood glucose lowering medications.
"This is because there is a wide body of evidence that shows surgery is an effective treatment option for Type 2 diabetes and can be cost effective for the NHS.
"However, many people who stand to benefit from this potentially lifesaving treatment are missing out due to needless barriers to obesity surgery services.
"Even people who meet the criteria for the surgery are being made to wait too long, even though we know that people with Type 2 diabetes benefit most from the surgery if it is carried out closer to the time they were diagnosed."
Figures published last month show there are now more hospital admissions than ever before due to obesity.
There were 440,288 admissions to England's hospitals in 2014/15 where obesity was the main reason for a person being admitted or was a secondary factor.
The figure is the highest on record and is more than 10 times higher than the 40,741 recorded in 2004/5.
Some 58% of women and 65% of men are overweight or obese and, in 2014/15, more than one in five children in their first year at school, and one in three in Year 6, were obese or overweight.
Prof Rubino described the surgery as "the closest thing to a cure" for the condition.
He said the guidelines represented one of the "biggest changes for diabetes care in modern times".