One in ten NHS trusts restrict operations for obese people or smokers, according to an investigation.
ITV1's Tonight With Trevor McDonald programme said 16 of the 152 trusts in England have policies restricting non-emergency surgery such as hip replacements.
Out of the 16, eight trusts held restrictions due to a patient's weight. One restricts on the basis of smoking only and seven NHS trusts are now restricting operations to both smokers and obese patients.
The programme, Too Fat For Treatment, examines whether patients are being barred from operations on medical grounds or as a cost-cutting exercise
Surgery decisions are often made on the basis of a patient's weight using the body mass index (BMI) which, critics say, unfairly rules out otherwise perfectly healthy patients.
Dr David Haslam, who devised the guidelines for obesity management in primary care in the UK, tells Tonight: "Technically speaking, a BMI of 30 plus means that you're obese.
"But that figure in itself tells us very, very little about fitness and your medical risk and so on because you can have a BMI of 35 and be absolutely the fittest person on the planet because you're fit, you're muscular, you've got wide shoulders; you've got a narrow waist."
"Whereas someone, a bloke for instance with stick arms and stick legs, but a big belly, they many not be obese in terms of BMI but there are too many high risks in terms of medical risk because of their abdominal circumference."
Guidance set out by the General Medical Council says care should not be refused or delayed because of a patient's lifestyle, but some critics say that is exactly what is happening.
Michael Summers, chairman of The Patients Association, tells the programme: "It's absolutely clear that many of the decisions have been made whereby patients are deprived of treatment, are made on financial grounds and not clinical grounds, and that is never acceptable in our view ... merely to send patients away because they are smokers is morally wrong and again, contrary to the rules which I think are set by the General Medical Council."
