Fern's found the right way to lose weight

Fern Britton's admission that her recent weight loss is the result of surgery, rather than willpower and a rigorous diet and exercise programme, serves to illustrate two points all too familiar to most doctors. Namely, that despite their protestations that they are fat and happy, no obese person is truly content with their shape, and that diet, exercise and even slimming drugs simply do not work for most people.

If you really need to drop four dress sizes, as Fern has, then surgery is probably the most effective option. But is it right that a cash-strapped NHS should fund such a drastic solution?

It is a controversial issue but there is a growing feeling among doctors that gastric surgery is much under-used in this country. In an ideal world obesity should be treated simply by encouraging a healthier lifestyle, but in practice the results from this sort of intervention are depressingly poor. And prescription-only slimming drugs don't seem to add much, either - weight loss using them is often disappointing and is reversed within a few months of the patient stopping therapy.

In 2002, when the National Institute of Health and Clinical Excellence (NICE) first appraised surgical treatments for obesity (bariatric surgery) there were fewer than 10 specialists in the country offering the treatment, compared with around 200 in countries like France and Italy where obesity rates are significantly lower.

The situation is improving here but not as fast as some experts would like. There are thought to be at least a million people in England and Wales alone who meet the criteria for bariatric treatment suggested by NICE (see below), yet just 3,000 operations are likely to be carried out during the current financial year.

No primary care trust (PCT) in the country will openly admit to refusing to fund bariatric surgery but only half rigidly apply the criteria laid down by NICE, with most setting the bar much higher. It is unclear why they are so reluctant given that NICE believes it makes financial sense in carefully selected patients. It concluded that the short-term costs - around £6,000 per patient for gastric banding (the most widely used procedure) - are balanced in the longer term by a reduction in obesity-related complications such as heart disease, cancer and diabetes.

And the resulting weight loss is pretty impressive too. Bariatric surgery remains by far the most successful of all the interventions offered by the NHS. Fern lost five stone, but results are often even more dramatic than that and the weight loss is often permanent. Something that can't be said for people who follow low-calorie diets or take slimming pills - most of whom eventually end up back at their original weight within a year or two.

It may be an effective solution, but it has more than its fair share of complications and it is no panacea. As Anne Diamond discovered to her dismay, it doesn't work for everyone, and there are significant risks involved. Although gastric banding is done using a minimally invasive keyhole technique, it still requires a general anaesthetic and the risks of complications like chest infections and blood clots are much higher in the very obese.

That said, most operations go smoothly and serious complications are unusual, and have to be balanced against the benefits - many of these patients won't be alive if they don't have the surgery.

Even so, bariatric surgery is always going to be very hard to get on the NHS, with fewer than one in 400 of those eligible under the NHS criteria being offered it in any one year, at a cost of around £20 million. To even be considered, NICE recommends that you should be:

aged 18 or over
be morbidly obese with a body mass index of 40 or above (or 35 and above if you already have a health problem such as diabetes or high blood pressure that would be helped by weight loss).
been under the care of a specialist at an obesity clinic and have tried and failed to lose weight using conservative methods (diet, exercise and prescription-only slimming medication).

Around half of all operations done in the UK this year will be performed privately - gastric banding costs around £7,000 a go and most surgeons apply exactly the same criteria to their NHS and private patients, so don't expect to be able to get it done unless you have a serious weight problem.