Hundreds of people under the age of 25 underwent weight loss surgery in the last three years, a major study has found.
The National Bariatric Surgery Registry (NBSR) said 108 men and 462 women aged 24 or under had obesity operations between 2011 and 2013, including 62 people under the age of 18.
It found more than 65% of obese patients with type two diabetes showed no sign of the condition two years after weight loss surgery, which includes gastric band, gastric bypass and sleeve gastrectomy operations.
Jonathan Wallace, 24, was dubbed the 'fattest teenager in Britain' before losing 24 stone due to gastric bypass surgery
On average, patients lost 58% of their excess weight a year after surgery, with the figure rising to 68.7% for gastric bypass patients alone.
The NBSR report, which looked at more than 18,200 operations, found the average body mass index (BMI) of patients undergoing weight loss surgery was 48.8, meaning that patients were almost twice the weight they should be for their height.
Nearly 40% of the young people were classified as super-obese, meaning they had a BMI of 50 or more.
Some 73.2% of men and 71.5% of women had what is known as functional impairment - meaning they could not climb three flights of stairs without resting.
But after surgery more than half of those patients (56%) could manage three flights without resting, the report found.
Some 61% of patients with sleep apnoea were able to come off treatment, the report found.
The report said bariatric surgery could offer "significant financial savings to the healthcare economy", but its chairman, consultant surgeon Richard Welbourn, said "deeply held societal prejudice" against obese people could limit access to surgery.
The mortality rate of patients after weight loss surgery was 0.07%, while the rate of post-operation complications was 2.9%.
An increasing proportion of men are seeking surgery, the report found. In 2006, 16% of patients were male while by 2013 the figure had risen to almost 26%.
Gastric band surgery
The report said: "The huge cost of treating diabetes has led to much focus on bariatric surgery as an effective treatment. Simply considering the reduced costs of diabetes treatment, surgery pays for itself within two to three years."
Welbourn, the chairman of the NBSR, said: "The NHS is saving money because patients are coming off their diabetes medication as a direct result of their bariatric surgery.
"This unique database provides clear evidence that bariatric surgery radically improves health for patients with severe and complex obesity.
"The challenges of raising awareness of the effects of bariatric surgery and increasing service provision are considerable.
"Many factors including deeply held societal prejudice and reorganisations within the NHS appear to be limiting the provision of surgery, which is much less than in other equivalent countries."
NHS England's medical director Sir Bruce Keogh said: "Obesity and bariatric surgery are rapidly rising up the NHS agenda as a consequence of social and lifestyle choices.
"As in all branches of medicine, prevention is better than cure, but this report clearly demonstrates that when required, bariatric surgery is effective and safe.
"This is based on detailed data on over 18,000 patients. The survival rate of over 99.9% and the decreasing length of time spent in hospital is all the more impressive given the increasing illness of patients being sent for surgery."
Clare Marx, president of the Royal College of Surgeons, said: "This audit shows compelling evidence of the cost-effectiveness of bariatric surgery for obese patients.
"Obesity is linked with a number of conditions including diabetes which are not only debilitating for patients but also create a significant financial strain on the NHS.
"It is important that bariatric surgery is not seen as an operation that takes place in isolation from other services.
"Surgeons should work closely with their colleagues in hospital and in the community to develop a care plan that supports the long-term health of patients suffering from obesity."