Leading article: An ethical trap for the health service

When the National Institute for Clinical Excellence (Nice) recommended in December 2006 that surgery be offered to grossly obese adults and children to control their weight, experts who attended the launch of its guidance said they expected "a few hundred" adults a year to have the operation – which costs £10,000 – rising to "a few thousand" in the future.

Yesterday, the Royal College of Surgeons (RCS) estimated that there were one million adults whose weight had ballooned to the point where they qualified under the Nice criteria and that 240,000 wanted surgery, yet just 4,300 got it.

The yawning gap between demand and supply goes some way to accounting for what the RCS describes as the "inconsistent" response of primary care trusts, leading in some cases to "unethical" behaviour. If you are expecting a queue of a few hundred patients and you suddenly find you have thousands, you have no choice but to cull the queue in any way you can.

That is what PCTs have been doing. The simplest way is to raise the bar for surgery from a Body Mass Index of 40 – the defining point of "gross obesity" – to a BMI of 45 or 50, which is what the RCS claims is happening.

It is a standard response when resources are short to ration care to those in the greatest need. It is also ethically desirable. It does not normally cause further ethical complications because it is not possible for patients to make themselves iller – and thus needier – than they already are. Obesity, however, is different. If you are not fat enough to qualify for surgery, you can always make yourself fatter. The RCS claims this is what some GPs are telling their patients to do if they want the National Health Service to help. Advising patients to make themselves fatter, however, increases their risk of diabetes, heart disease, joint problems and other ailments. That is unethical. Patients, their carers and the NHS are thus caught in a trap.

Surgery is one of the few measures of proven effectiveness for gross obesity. But its cost – and not inconsiderable risks – rule out its provision on a wide scale. We must look elsewhere for solutions to the epidemic.