Figures released by the Royal College of Surgeons revealed that severely obese patients are able to come off disability benefits and return to taxed employment, dwarfing the £8,000 cost of the procedure.
It said the NHS must now fund more operations – for the benefit of patients and the economy.
Marcus Reddy, a consultant surgeon at St George’s Hospital in London, said: “It has been a falsely held belief that bariatric surgery is expensive. It’s not.
“It’s very cheap. It’s something that will help all of us in the economy.”
Some surgeons are claiming that obese operations could save the economy millions
Analysis by the well-respected Office of Health Economics showed, if a quarter of obese patients had the size of their stomachs reduced, it would cost the NHS £546m.
But, over the next three years, the NHS would save £104m as their health improved and the benefits bill would fall by up to £450m.
So many housebound patients would be fit to return to work that the economy would get a boost of £1.8bn.
Mr Reddy said: “In the short term it is new expenditure. But, after surgery, patients’ diabetes is resolved, their medication reduced and they’re not attending hospital so frequently. It’s staggering.”
Anthony Colyer, who has lost 6st since having the surgery a year ago, said the NHS should do more of the operations.
From taking 14 tablets to treat medical conditions related to obesity, he is now taking just one and no longer fears his size will cost him his job.
Mr Colyer said: “I don’t go to my doctors as often. I don’t expect to need any hip operations or knee operations because riding my bicycle tells me all my joints are good. I don’t get any aches. So I think surgery is incredibly important.”
About 240,000 obese patients need – and want – weight-loss surgery on the NHS.
Last year, just 3,600 actually had it.
But the Department of Health made no commitment to increase funding for operations.
Health minister Paul Burstow said: “Our ambition is to encourage healthier lifestyles and reduce the need for this type of treatment.”