Weighing up the options on obesity

Keeping weight off is much harder than losing weight in the first instance. AAP

Prevention is the cornerstone of society’s response to the current obesity epidemic. But even if no more people were to gain much more weight, those who are already obese face serious health problems.

The most critical issue in developing therapies for obesity is the durability of weight loss; many people can successfully lose weight, but few manage to keep it off for a long time.

So, if we are to effectively help those struggling with obesity, we must evaluate the long-term viability of various therapeutic strategies.

The options

1) Lifestyle changes remain the basis of any effective therapeutic intervention in a chronic disease like obesity.

Yet 40 years of messages about lifestyle changes have not had the desired effect: more people are now obese or overweight than ever before.

2) Drug therapy for obesity has offered glimmers of hope, and remains a goal for many scientists and physicians.

Unfortunately, in the recent past we’ve seen many promising drug therapies fail to demonstrate a level of weight loss that outweighs the risks of side effects.

There’s reason to remain optimistic that further developments will produce drugs that can safely facilitate clinically meaningful weight loss, but currently approved options are not particularly useful because they do not result in enough weight loss.

3) After failing to lose weight with diet, exercise or medication, the final option is surgery.

While too expensive, and too resource intensive to be the cure for the high levels of obesity already seen in the Australian population, surgery is an excellent therapy for a portion of the people struggling with obesity.

It is usually recommended for people with body mass index (BMI = weight(kg)/height(m²): BMI Calculator) of over 35 who have other illnesses, known as co-morbidities, or those of a BMI of 40 and over.

Laparoscopic adjustable gastric banding (LAGB) is the most commonly performed procedure in Australia and the United States. It has been shown to be extremely safe surgery, and is now often performed as a day-stay procedure.

LAGB involves the keyhole placement of an adjustable silicone band around the very top portion of the stomach.

This induces a sensation of early satiety and prolonged satiation, which leads to smaller meals being consumed less frequently, thereby reducing the total daily caloric intake.

Our studies have shown the weight loss achieved with LAGB is significantly greater than diet and exercise programmes, bringing with it significant improvement in health and wellbeing.

This translates to improved life expectancy for the individual and an economic benefit to the community.

An alternative surgical technique, gastric bypass surgery, is more invasive and carries higher risks.

This technique can also be performed through the keyhole approach and involves dividing the stomach just below the junction of the stomach and the oesophagus thereby creating a small pouch of stomach.

The small intestine is then connected onto this small pouch and the digestive juices from the liver and pancreas are diverted to join the food stream 150 centimetres away from the stomach.

This means there is only a small volume of stomach to accommodate the meal restricting the size of the meal, and that the duodenum is bypassed, thereby affecting food absorption.

Elsewhere in the world, gastric bypass has been found to result in greater weight loss than LAGB. But meta-analyses suggest that at five years after surgery, weight loss is equivalent between the procedures.

But questions about LAGB’s efficacy have recently been raised by some Belgian surgeons, whose study generated much controversy.

Looking at the outcome for a portion of their patients who received adjustable gastric bands over the preceding 12 years, the study questioned whether banding was the best procedure for these patients.

It examined the experiences of 151 patients, who were treated over four years in the mid-1990s. They were among the first to be treated with LAGB anywhere in the world when surgeons had the least experience with LAGB – at the start of the procedural learning curve.

It found a high erosion rate, which suggests a technical error and the rates of band removal or conversion to gastric bypass are high. This is clearly a decision made by the surgeon, and suggests that they are aware that the surgery is not performing as well as it should.

In Australia, the relatively superior efficacy of LAGB is due to extensive post-surgical patient education and follow-up – a consequence of our supportive health care reimbursement system.

At follow-up visits, patients are counselled on food choices and eating styles. They are checked for early signs of complications and their band system may be adjusted.

The patients in the Belgian study, on the other hand, reportedly had infrequent and incomplete follow-up visits.

What next?

The obesity epidemic is accompanied by the lagging epidemics of diabetes and heart disease, as well as a raft of other chronic conditions.

Surgery remains the most effective option for treating obese patients even though there is an ongoing debate about the better one of the two major surgical techniques.

Believable data on these parameters on large cohorts of patients will enable meaningful comparison of the two surgical procedures, and comparison with other, non-surgical approaches to treat obesity. We look forward to continuing to contribute to this debate.

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