The long-term health benefits from living lighter are significant. For those whose weight consistently remains a struggle, or is severely limiting, bariatric surgery could be an option. Far from a quick fix, bariatric procedures are irreversible, require a hospital stay and mean a change in lifestyle. 

Despite our society becoming more educated with dietary interventions and exercise regimes, the rates of obesity continue to increase steadily each year. The number of people overweight or obese has risen from 57% in 1995 to 67% in 2018. This is due to multiple factors significantly more complex than just fast foods or a lack of self-control.

Surgeon Dr Matt Henderson from St John of God Murdoch Hospital said Body Mass Index (BMI) was commonly used to measure the degree of excess weight a patient was carrying.

“BMI neatly divides patients into groups from underweight through to Class 3 Obesity,” he said.

“Although it is routinely used today, not many people know it was devised in the 19th Century by a Belgian statistician, which makes it more than 100 years old. Some of the issues around the use of BMI to determine weight are that it does not take into account muscle mass, gender or ethnicity.”

BMI was used in 1991 during the National Institute of Health (NIH) meeting which brought together multiple specialists to advise on obesity surgery. The group supported surgery for patients with BMI >40 and for patients with BMI 35-39 with comorbidities, which included cardiopulmonary issues, diabetes mellitus and quality of life issues. These guidelines were adopted universally, and we still see them in bariatric literature today.

“Bearing in mind the issues with BMI and the fact that the NIH meeting is 28 years old, there has been a move to reconsider who will benefit from surgery for obesity,” Dr Henderson said.

“If your BMI is greater than 30, I would recommend discussing with your GP if you could benefit from surgery.

“Several operations exist for weight loss. At a consultation, these are discussed in depth and allow the patient and the doctor to make the best decision for you.”

Sleeve gastrectomy

This is the most popular procedure for weight loss and accounted for 70% of all weight loss operations last year.

This keyhole operation is suitable as both a primary or revisional procedure in most patients. Sleeve gastrectomy is a restrictive procedure, where the stomach is reduced in size from a sac shape to a tube that holds around 150ml. It involves removal of over 75% of the stomach, which is divided with a special stapling device. It used to be the first stage of the BPD bypass procedure but has been performed as a stand-alone procedure for over five years. The operation significantly reduces hunger by reducing levels of the hormone Ghrelin which is predominantly produced in the upper stomach and is removed during this procedure. By affecting the hormones that drive hunger and limiting the amount that patients can eat, these two factors together enable patients to achieve an almost 70% excess weight loss in the first 12 months after surgery.


  • Keyhole surgery, usually takes just over an hour and requires three to four days in hospital
  • No adjustments required
  • No foreign material to get infected or leak
  • No fixed obstruction for food to get stuck
  • Normal dietary intake by the majority of patients
  • No malabsorption
  • Significantly safer than Bypass surgery
  • More effective and better tolerated than Gastric Banding
  • Reliable – provided you follow a sensible diet and exercise regularly then good results are expected
  • Low risk of requiring further surgery


  • Not reversible (however most people considering weight loss surgery are after a permanent solution)
  • Risk of leakage from the staple line (<1%) in the first two weeks is a major potential complication, which may require further surgery and intensive care


  • 60-70% average excess weight loss (EWL) at one year

Gastric Bypass

This is a combined restrictive and metabolic procedure. The top of the stomach is divided to create a small pouch. The small bowel is divided and then reconstructed to allow food to pass directly to the small intestine bypassing most of the stomach and the duodenum. The bypass component alters the level of various gut hormones normally produced in the duodenum which controls how the body processes and metabolises food.


  • Highly effective for weight loss and diabetes
  • Effectively stops bile and gastric reflux
  • Discourages eating sugar and fats which cause “dumping syndrome”


  • More complex surgery with higher risks
  • Mild malabsorption which requires lifelong nutritional supplementation and annual screening blood tests to prevent vitamin and mineral deficiency
  • Potential for anastomotic stricture, ulcers, pouch dilatation
  • Small future risk of internal hernias causing bowel obstruction which can require emergency surgery and may be life threatening
  • Further revision surgery is difficult with limited options


  • 70% average excess weight loss at 1-2 years

Although gastric bypass has been the most popular bariatric procedure in the northern hemisphere for the past decade, more recent data demonstrates that sleeve gastrectomy can achieve similar outcomes with lower risks and has therefore been the preferred primary procedure.

Gastric bypass is still a useful option to consider for patients with difficult to control diabetes, uncontrolled gastro-oesophageal reflux or as a revisional procedure.

For more information about bariatric surgery at Murdoch Hospital click here.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s