Paul Mason weighed up to 70 stone before the surgery
The surgeon who operated on an Ipswich man, who is believed to be the heaviest man in Britain, says surgery was the only option.
Paul Mason consumed 20,000 calories a day and weighed as much as 70 stone before having a gastric bypass operation in 2010.
"There was no other choice," said Shaw Somers, surgeon. "It was either that or wait for the inevitable."
Mr Mason is the subject of a Channel 4 documentary, Britain's Fattest Man.
In the programme, Mr Mason speaks about his pre-surgery eating habits.
"Fry up every morning, four sausages, a whole packet of bacon, four eggs, two pieces of fried bread, hash browns," he said.
"At half ten I'd have sausage rolls, pastries. Lunch would be fish and chips, kebab, and then in the evening time it would be another takeaway.
"In a day I would eat 30-40 chocolate bars, three-four multipacks of 24 crisps."
Mr Somers, a consultant bariatric surgeon, performed the operation at St Richard's Hospital in Chichester.
He defended the public sector's financial support for Mr Mason's care.
Shaw Somers says surgery was the only option for Paul Mason
"I think people have a right to question how taxpayers' money is spent, but what people often fail to understand is how much it costs to keep someone like Paul alive in terms of daily care, his various allowances that he's perfectly entitled to because he's too big to live a normal life.
"For whatever psychological reason, Paul just could not kick the habit and he got past the point of return.
"There's almost a million people in this country with the same sort of problem and it's like treating someone with alcohol, smoking, drugs and other addictions.
"You can either ignore it and say 'it's your fault, your problem' or we can say 'actually it's costing us more to ignore it than it would do to treat it properly'."
Mr Somers says the surgery was "pretty straightforward" and that he is pleased with how Mr Mason is recovering.
"He's doing very well," said Mr Somers. "He's really grasped this chance and is working his best to make it work for the future.
"He's really risen to the challenge and is doing his very best."
Britain's Fattest Man is on Channel 4 on Wednesday, 5 January at 9.30pm.