The standard advice to control weight is by combining healthy eating and regular exercise. But most overweight people find this difficult and long-term success rates for weight loss are generally low. As a result, operations known as bariatric surgery have increased almost ten-fold in the past decade.
This article was first published in October 2011.
A sensible rate of weight loss is around 0.5kg to 1kg (1lb to 2lb) a week. To achieve this, you need an energy deficit of 3,500kcal to 7,000kcal a week, which means eating 500 to 1,000 fewer calories a day.
You can do this by replacing high-fat foods with those that are low in fat such as fruit and vegetables, unrefined carbohydrates and lower-fat dairy products, and by being more physically active.
It's also important to watch the size of your portions. This can be difficult, because over time you can lose touch with what's a sensible amount of food.
There are few drugs for obesity, and their effect is limited, so doctors have increasingly been looking at other ways to help. But what does obesity surgery involve, and what are the risks?
The aim is to help someone reduce their weight generally across the whole body, not to reduce fat in specific areas such as a large belly. So operations such as liposuction or breast reduction aren't considered as bariatric surgery for obesity, but as cosmetic procedures instead.
Bariatric surgery can be divided into two types:
These operations reduce the amount of food a person is able to take in at any one time by decreasing the size of the stomach, so that you feel 'full' soon after you start eating. It's usually done by putting a band around the stomach, leaving only a small pouch above the tight constriction. Another alternative is a balloon inflated inside the stomach.
These operations usually bypass part of the intestines to reduce the amount of food which is absorbed into the bloodstream.
There are several techniques, but two operations are most commonly used:
After surgery people are advised to:
There's no doubt that surgery can be an effective way to lose large amounts of weight. After gastric band surgery, about 40 to 60 per cent of excess weight may be lost, while slightly more (about 60 to 70 per cent of excess weight) may be lost after a Roux-en-Y.
More importantly, surgery has been shown to considerably reduce the risks of obesity-related conditions such as:
Surgery reduces the risk of dying from these conditions by 30 per cent or more. It can rapidly reverse Type 2 diabetes, sleep apnoea and gastric reflux - for example one study found that as many as 85 per cent of people with type 2 diabetes prior to gastric band surgery showed no sign of the disease two years later.
Bariatric surgery also brings psychological benefits, from better mood, self-esteem and relationships to improved work performance. However rates of divorce and even suicide are higher after surgery, and some people develop large folds of loose skin after losing large amounts of weight, but cosmetic surgery to remove these may not be funded on the NHS.
One of the main risks is that the weight loss will not be maintained long term. Surgery isn't just an opportunity to eat freely, and those who have an operation have to be prepared to make life-long changes in their lifestyle and eating habits. But some people simply find ways to get around the effect of surgery, by eating small amounts more often or even drinking liquidised forms of their favourite foods such as chocolate.
Weight loss is usually greatest in the first year, then slows and may even reverse. In one study, by six to nine years, only seven per cent of people had lost all their excess weight and nearly one in four was once more morbidly obese.
There are also many possible complications including:
After Roux-en-Y a person typically has a one in ten chance of needing to be admitted to hospital within a month, with complications including infection, haemorrhage, and strictures. Mechanical complications such as an internal hernia are rare but nutritional problems such as thiamine and calcium deficiency are considerable. There is also an increased risk of gallstones. The 30-day mortality rate (risk of death one month after surgery) of Roux-en-Y is 0.5 per cent.
After a gastric band, mechanical complications are more frequent than with Roux-en-Y but often less severe and include poor weight loss due to band leakage in seven to eight per cent of patients, and pain/vomiting/food intolerance due to an over-tight band in six to seven per cent Other risks include erosion or pressure ulcer, and gallstones. A significant number of people need to have their band adjusted soon after the operation. The 30-day mortality rate of LAGB is 0.1 per cent.
The National Institute for Health and Clinical Excellence (NICE) recommend that initial treatment for obesity should be diet, exercise, modifying lifestyle, drug treatments and support. Surgery should only be considered as a 'final option' when someone has severe obesity with a BMI over 40 and isn't responding to these other steps, although people with a BMI of 35-40 may be eligible if they have other high risk conditions such as:
For those who are very severely overweight, with a BMI over 50, bariatric surgery may be considered as a first line option.
Some experts, faced with growing numbers of obese people unable to lose weight through diet and exercise who need costly treatment for related conditions, are calling for earlier use of surgery especially as techniques such as the gastric band become simpler and cheaper.
Even though it has been estimated that if just 25 per cent of eligible patients underwent bariatric surgery, the NHS could save £1.3 billion over three years, the operations aren't widely available on the NHS.
NICE has published a strategy for treating obesity, but it's only a framework and primary care trusts (PCTs) can decide their own individual strategies. With increasing demands on health funds, and many PCTs making cutbacks, bariatric surgery isn't prioritised in many areas.
So treatment varies - some call it a 'postcode lottery' as to whether the NHS will pay for bariatric surgery if you need it. Many PCTs, for example, will only offer surgery when the BMI is above 40, even if there are related conditions. Others categorise patients by their waist size (central obesity, or 'apples shapes' are at greater risk of other conditions). The World Health Organization recommends that people of Asian origin should be offered treatment at 2 kg/m2 lower BMI levels because of their increased risk of diabetes and heart disease, but this is rarely put into practice.
In addition to these criteria, the patient's age and state of health may be taken into account - many surgeons feel uncomfortable operating on those under 18 (feeling that it's more important to instil healthy habits about diet and exercise) or over 65 years (even though many elderly people would benefit hugely with regard to reducing diabetes and heart disease, and improving mobility).
So you may not be offered bariatric surgery on the NHS in your area. The cost, if you want to consider having surgery privately, is high - the average cost for a gastric band is about £7,000 - £8,000 for example.
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