THE word bariatrics was derived in the 20th century from the Greek "baros" (weight) plus "iatrics" (medical treatment).

Bariatrics is defined as the field of medicine that offers treatment for a person who is overweight, with a comprehensive programme including diet and nutrition, exercise, behaviour modification, lifestyle changes and, when indicated, the prescription of appetite suppressants and other appropriate medications.

Bariatrics also includes research on obesity, its causes, prevention, and treatment.

It follows then that bariatric surgery is the science of treating overweight subjects by surgical means. Surgery for the obese is not new. In the past it was as simple (and as crude) as simply wiring a patient's mouth shut so he or she was only able to take in liquids.

However this was associated with a high morbidity and mortality and over the years more sophisticated techniques have emerged.

Surgery may be divided into two categories:

1. Restrictive, or

2. Malabsorptive

Restrictive procedures aim to create a small stomach pouch with a narrow opening, and the aim is to limit food intake and delay gastric emptying.

Malabsorptive procedures bypass various parts of the small intestine so that food absorption is reduced.

Some examples of restrictive operations are "Gastric Stapling" (or Gastroplasty) and the new and popular "Adjustable Gastric Banding". In this operation, an adjustable band (fluid-filled, with a reservoir) is wrapped round the stomach to form a small pouch with a narrow outlet.

Malabsorptive procedures are more complicated operations with colourful names like "Proximal Roux-en-Y gastric bypass", "Sleeve Gastrectomy" and "Biliopancreatic Diversion".

The gold standard is the "Proximal Roux-en-Y gastric bypass", which is a combination restrictive-malabsorptive procedure. However it is difficult to perform, requires a long hospital stay, and can only undertaken by experienced surgeons.

Adjustable gastric banding is popular because of its simplicity. It can be carried out laparoscopically through a small skin incision, which means that an open operation is not required. This translates into a shorter hospital stay.

In this procedure, a long, thin fluid-filled tube is wrapped around the stomach and this tube can be tightened around the stomach by pumping in more fluid, thus limiting what the patient can eat. This is done gradually so the patient can adjust to it.

Who needs bariatric surgery? Surgery is indicated for those with a BMI of 40 or higher; or 35 and above if the patient has associated risks like severe sleep apnoea (where the patient stops breathing during sleep), heart problems directly related to obesity (obesity-related cardiomyopathy) or severe diabetes.

In addition there should be evidence that the patient has tried, but failed to lose weight through conventional means like diet, exercise and medical treatment.

The subject should also be psychologically sound, able to understand the surgical procedure, the risks involved and the post-operative management.

Preoperative assessment should be carried out by a team comprising of a physician, a surgeon, a nutritionist and a psychologist.

A surgeon told me that after surgery, one of his patients used to pour liquid chocolate down her throat - she complained that anything else made her feel nauseated! Hence the importance of psychological screening.

In the past there has always been some doubt as to whether the benefits of bariatric surgery outweighed its risks. Two large studies reported in the New England Journal of Medicine in August 2007 have confirmed that bariatric surgery may be life-saving in selected patients.

The editorialist George Gray summarises: "Thus, the question as to whether intentional weight loss improves life span has been answered, and the answer appears to be a resounding YES."

In another study published in the January 2008 issue of the Journal of the American Medical Association, an Australian study using the Adjustable Gastric Banding technique showed that 73% of their patients undergoing this procedure had achieved remission of their diabetes versus 13% in the conventionally treated group. However, the accompanying editorial suggested that the excellent results were the result of a specialised team, and may not be reproducible by less experienced units.

In our local setting, bariatric surgery units are just being set up. With time we should be able to emulate the results of specialised units elsewhere in the world.

There is no magic cure for obesity. The foundation of treatment is still diet and exercise. It would be naive to believe that bariatric surgery is a risk-free short cut to a beautiful figure. Patients still DIE from surgery, more so obese subjects with associated diseases like diabetes or hypertension.

The most "successful" operation will still fail in the medium to long term if it is not followed up by diet and exercise.