Figures have revealed that the application of weight-loss surgery has soared by 785% as the NHS struggles with the "overwhelming" burden of obesity.
Specialists have suggested that certain doctors could be "skirting around the rules" and allowing patients to undergo surgery before insisting on months of lifestyle alterations and medical treatments.
Over the past five years, procedures carried out in England for the most obese people have risen dramatically, the NHS Information Centre said.
By 2008/09 procedures had increased to 4,246 from just 480 in 2003/04, data shows.
Tam Fry, from the National Obesity Forum, said: "We have alternative ways of losing weight but when people realise this is a possibility, they could go for it.
"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."
Peter Sedman, bariatric surgeon and spokesman for the Royal College of Surgeons, said: "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."
The upward trend of operations suggests 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.
Health Minister Paul Burstow said: "Our ambition is to encourage healthier lifestyles and reduce the need for this type of treatment.
"Our public health white paper later this year will set our plans to help people lead healthier lifestyles in more detail."
Copyright © Press Association 2010
"It's no point in blaming doctors about skirting the rules before subjecting obesity surgery as the number of persons opting for this surgery has grown to 785%. At this rate the only solution will be for the concerned authorities to foresee the number of patients in the coming years and plan the infrastructure requirements" – Name and address withheld