Is surgery the best way to slim?

Every day I help people struggling to lose weight. The media is full of 'miracle stories' of people who've gone from a size 30 to 12 after surgery, so it's hardly surprising that many patients see weight loss surgery as an easy option. It isn't.

When I qualified as a GP, one UK adult in eight was obese. Today, that figure is one in four and rising all the time. The more overweight you are, the greater your health risks - heart attackstroke, type 2 diabetescancer and arthritis among others. Experts argue constantly over the main causes - less exercise, more calories, too much sugar, constant snacking or 'grazing' rather than sitting down for meals. We know some people inherit a tendency to put on weight more easily, but if it was all down to changing genes the rise in obesity would have taken thousands of years, not decades.

Every day I help people struggling to lose weight. The media is full of 'miracle stories' of people who've gone from a size 30 to 12 after surgery, so it's hardly surprising that many patients see weight loss surgery as an easy option. It isn't.

All surgery carries risks of complications, including death. And once you've had the surgery, it's definitely not business as usual. You'll need to have long-term follow-up and make lifelong changes to your lifestyle to stay healthy.

Who decides what's overweight?

Weight ranges are calculated using body mass index (BMI) - 18-25 is 'ideal', 25-30 'overweight', 30-40 'obesity' and over 40 'potentially life-threatening obesity'. Waist size also matters - a tendency to put on weight round your midriff carries higher health risks.

People of South Asian origin have different criteria. For them a BMI over 23 is considered overweight and over 28, obese. However, some doctors say the figures should be stricter still because people of South Asian origin are at much higher risk of type 2 diabetes and heart disease.

Who should consider weight loss surgery?

The National Institute for Health and Care Excellence (NICE) advises surgery as a last resort, only where serious attempts to lose weight with lifestyle haven't worked. They only recommend it for health reasons, never just appearance. While the cutoff is usually a BMI over 40, some people are considered with a BMI over 35 if they have serious health problems (type 2 diabetes, high blood pressure etc) which could be improved by weight loss. If you have psychological problems causing you to overeat you won't be considered for surgery until these have been treated.

Last month NICE recommended that more people with diabetes should be considered for weight loss surgery, on the grounds that the cost to the NHS is offset by the savings from fewer weight-related health complications in the longer term. But even they include significant caveats. NICE recommends that for at least the first two years after surgery, patients are followed up within a multidisciplinary team with access to dieticians, psychology, nurses, exercise therapists, and monitoring for vitamin and mineral deficiencies. After two years, NICE recommends that there is at least annual monitoring of nutritional status with supplements if needed.

And even if the risks were thought to outweigh the benefits in an individual case, weight loss surgery will never be the solution to the bigger picture. In 2012-13 there were about 138 surgeons in the NHS doing bariatric surgery, between them providing about 5,650 operations. There are hundreds of thousands of people with a BMI over 35 in the UK - the level at which NICE recommends surgery should be considered if you have type 2 diabetes. The figures for surgery are rising every year (there were just 858 procedures in the UK in 2006-7), but it would take decades just to train the surgeons.

What other help is available?

The NHS recognises how hard it can be to lose weight, and there are a host of services available to help. Anyone can make an appointment with their practice nurse - it helps to bring a diary of everything you've eaten and drunk for a week or two. She can tailor a plan to you and refer you to a dietician if necessary.

There are also lots of lifestyle classes, which combine exercise and diet tips - your nurse will know what's available in your region. Your council may also run classes where you can make new friends and get fit - most have classes aimed at every age and fitness level.

Bypass or banding?

There are actually two very different kinds of weight loss surgery - gastric banding and gastric bypass. Banding is a shorter procedure, usually carried out with keyhole surgery taking about an hour. A band is passed round your stomach, dividing in into two pouches - food you swallow goes into the smaller pouch, making you feel full much quicker. The band can be inflated afterwards to change the size of your 'new' smaller stomach.

Sometimes bypass can be done with keyhole surgery. A pouch of stomach is separated off and attached directly to your small intestine. This cuts the amount you can comfortably eat but also reduces the amount of your food you absorb.

Most people lose about half their excess weight after banding. This is less than the average two thirds of excess weight lost after bypass, but banding is an easier operation to do, with fewer short- and long-term complications.

Should surgery be available on the NHS?

There is a school of thought that obesity is 'self-inflicted' - down to greed and laziness. Why should the cash-strapped NHS spend money on treating a lifestyle choice? Of course it's not that simple. We help people addicted to smoking or alcohol - is 'food addiction' any different? And of course, diseases caused by obesity cost the NHS hundreds of millions of pounds. There's no doubt that surgery cuts obesity-related disease, with all the costs it carries, in the long term.

With thanks to 'My Weekly' magazine where this article was originally published.

Dr Sarah is unable to provide medical advice or respond directly to questions concerning your health. If you have health concerns we recommend contacting your GP.