The number of gastric bypass operations carried out by the NHS in England has risen five-fold during the past five years, new figures have revealed.
Some 5,407 procedures took place in 2011-12 to help obese patients lose weight, compared with just 858 in 2006-07 - a 530 per cent increase.
Figures released to the Press Association by the Health and Social Care Information Centre show a further 1,316 gastric band operations were completed between April 2011 and March 2012 - nearly double the 715 procedures over the same period five years earlier.
There were also 1,618 gastric band maintenance operations and 124 procedures to remove the weight-loss mechanism in 2011-12.
The British Obesity and Metabolic Surgery Society said gastric bypass operations had proven to be the most effective surgery to ensure long-term weight loss.
The society has now called on the Department of Health to guarantee patients have equal access to the treatment.
BOMSS president Alberic Fiennes said: “There is compelling evidence that weight-loss surgery to treat the most severely affected is one of the most clinically effective, safe and cost effective treatments available.
“There are about 1.5 million such adults in the UK. They face premature death, disease and disability brought on as a direct result of their condition.
“These can be prevented, improved or eliminated by surgery. While the increase in bariatric surgery is welcomed by the BOMSS and the Royal College of Surgeons, we remain concerned that there is unequal access to treatment across the UK.
“We therefore call on the Department of Health to invest in a long term strategy to ensure that all patients have equal access to this life-saving treatment.”
Mr Fiennes added: “Evidence suggests that gastric bypass operations may be more effective in the long-term. It also has also been shown to bring about a direct and immediate improvement in patients with type 2 diabetes, in addition to the benefits of weight loss.”
Weight-loss operations, sometimes called “bariatric surgery”, work by restricting the amount of nutrients that can be digested and absorbed by the intestine.
Gastric banding involves reducing the size of the stomach with a band fitted around it, while a gastric bypass re-routes food to a small stomach pouch created by surgeons. A third, less frequently used procedure, removes a portion of the stomach.
The figures for NHS hospitals in England show a total of 18,577 gastric bypass and 7,650 gastric band operations were carried out between April 2006 and March 2012.
There were 433 surgical procedures to remove gastric bands over the same period.
NHS figures also show 4,581 gastric band maintenance operations were completed between April 2009 and March 2012.
Weight loss after a gastric bypass is usually more impressive than after a gastric band, according to the NHS website.
Most people with a gastric band will lose around half their excess body weight, whereas the majority of patients with a gastric bypass will lose around two-thirds of the excess body weight.
The risk of any sort of complication after a gastric band is around one in 10 compared to one in five for a gastric bypass.
The risk of death shortly after a gastric band is around one in 200 compared to one in 100 for a gastric bypass.
Patients are required to take nutritional supplements for the rest of their lives following a gastric bypass procedure.
Health minister Simon Burns said: “We want people to live healthier lives so they do not need to resort to surgery, but as a last resort, doctors can advise procedures like these are undertaken.
“We are working with charities, local government and industry to make it easier for people to make better choices to prevent obesity in the first place.
“This year a third of meals and takeaways served from popular high street chains will contain calorie information and over a million families are involved in our Change4Life campaign - helping people to eat well and move more.”