There has been a 785% rise in weight-loss surgery over five years, NHS figures showed today.
Data compiled by the NHS Information Centre revealed a rapid rise in the number of operations carried out for the most obese people in England.
Data for 2003/04 showed there were 480 procedures, rising to 4,246 in 2008/09.
The upward trend suggests the figures for 2010 could be even higher.
From 2003/04 to 2004/05, the number of procedures jumped from 480 to 747.
It then rose again the following year to 1,023, then 1,928 in 2006/07, 2,703 in 2007/08 and 4,246 in 2008/09.
Of operations carried out in 2008/09, 42 involved removing part or all of the stomach.
Another 1,378 included fitting a gastric band to make the stomach smaller, 504 were for stomach stapling and 2,210 involved a gastric bypass.
Some 124 operations involved inserting a "bubble" in the stomach to fill it up.
People may have undergone more than one procedure in the same operation.
The NHS Information Centre says its data is the most reliable available for the total number of operations carried out on the NHS.
The National Institute for Health and Clinical Excellence (Nice) recommends the surgery only for the morbidly obese (body mass index of 40 or more, or 35 if there is another existing condition which could improve with surgery, such as diabetes).
But people must have failed on other methods, such as traditional diets, first.
Tam Fry, from the National Obesity Forum, said: "These figures just show how bad things have got with the obesity epidemic.
"We have alternative ways of losing weight but when people realise this is a possibility, they could go for it.
"Worse still, there is a premise that if you feed yourself up you get to the bar - 35 BMI with co-morbidities or 40 without - then the operation would be yours.
"These operations cost money and the PCTs are trying to raise the bar of who's eligible.
"A lot of doctors are also starting to skirt around the rules and not insist on months of lifestyle change and pharmaceutical treatment - instead they are going straight for surgery.
"There's something in the order of 500,000 people who might be eligible for surgery.
"Those patients will be demanding this on the NHS, and a lot of doctors will think if it's preventing years of diabetes, cardiovascular conditions or other ill health, then it's worth it.
"It takes an age for a patient to slim down, but one flick of the surgeon's knife will address the problem."
Peter Sedman, bariatric surgeon and spokesman for the Royal College of Surgeons, said: "The number of operations in the UK has increased so dramatically partly because of the rise in obesity but also we are beginning to catch up with a backlog that has been building for decades and we are only now beginning to catch up with the US and other European countries in providing this care.
"There are a significant number of people for whom surgery is the only remaining option as all other methods of treatment have failed.
"The number of morbidly obese patients in the UK is increasing rapidly and we need to continue to put even more resources into what is proven to be a successful and cost-effective method of treatment.
"The burden on the NHS in years to come in obesity-related illness will otherwise be overwhelming."Reuse content