Obesity surgery

Current estimates suggest that around 31 per cent of the adult Australian population is obese. The associated health risks of ‘morbid obesity’ (unhealthy weight) include diabetes, heart disease, hypertension, sleep apnoea, depression, arthritis, certain cancers and reduced life expectancy.

Obesity surgery is the most durable and effective treatment for severe obesity. It should be considered in patients who have a BMI > 40, or a BMI >35 with associated health problems such as diabetes. In addition to weight loss, obesity surgery also leads to improvement in obesity-related health problems and quality of life. In the year 2020-21, just over 18,000 obesity operations were performed in Australia. Modern obesity surgery is performed using keyhole techniques, and is considered very safe with complication rates between 1-5%, depending on the type of surgery.

Obesity surgery is best considered as a tool. To obtain good long-term results, it is very important that patients are supported through their weight loss journey, to assist with permanent changes to their eating habits and lifestyle. Typically an obesity surgery service will include many health care professionals, including dietitians, nurses and psychologists.

Calculating your body mass index

There are various ways to categorise the degree of overweight and obesity. A popular and easy method is the body mass index (BMI). This should only be considered as a guide. To calculate your BMI, divide your weight in kilograms (kg) by your height in meters squared (m2). The resulting figure is your BMI. A person with a BMI of 40 or more is at a much higher risk of suffering from obesity-related disorders, such as diabetes, reduced mobility or high blood pressure.

The categories are:

• less than 20 - underweight
• 20 to 25 - normal weight range
• 25 to 30 - overweight
• 30 to 35 – mild obesity
• 35 to 40 - moderate obesity
• more than 40 – severe obesity

For example, if you weighed 110 kg and were 1.55 m tall, you would calculate your BMI by:

• working out your height in metres squared (1.55 m x 1.55 m = 2.4 m)
• dividing your weight by your height in metres squared (110 kg2.4 m = 45.8)

Your BMI would be 45.8.

The Better Health Channel has a Body mass index (BMI) calculator for adults and one for children and teenagers.

Obesity surgery techniques

The commonest techniques of obesity surgery in Australia include:

• Gastric banding (LapBand)
• Sleeve gastrectomy
• Gastric bypass

Gastric banding (LapBand)

Gastric banding was the predominant operation in Australia for several decades, but has now been largely replaced by sleeve gastrectomy and gastric bypass. By the year 2020-2021, gastric banding represented only 0.8% of all obesity surgery performed in Australia. Gastric banding involves placing a plastic ring around the top of the stomach that is connected by thin plastic tubing to a port underneath the skin. By adding or removing water from the port, the ring can be made tighter or looser. Patients with gastric bands need to eat slowly and chew their food very well. Eating red meat or bread is frequently problematic. Gastric bands can be inserted and removed by keyhole techniques.

Sleeve Gastrectomy

Sleeve gastrectomy is the most common obesity surgery procedure in Australia. By 2020-21, it represents 81% of surgeries carried out in Australia. “Sleeve” surgery involves a keyhole operation to remove a portion of the stomach, reducing its size to that of approximately a banana. In addition to its restrictive effect, this surgery also alters the hormonal signalling between the gut and the brain. Patients experience drastically reduced hunger levels, eat small meals, and as a consequence lose a large amount of weight. Some patients can experience increased heartburn symptoms after a sleeve gastrectomy.

Gastric bypass

There are several different types of surgery that fit into this category, including Roux-en-Y gastric bypass (RYGB) and One Anastomosis (or “mini”) gastric bypass (OAGB-MGB).

All have in common a combination of creating a small section of stomach to receive food, along with bypassing (“short-cutting”) the first part of the small intestine. Like the sleeve, these surgeries alter the signalling between the gut and the brain to reduce hunger levels. Patients can eat a wide range of foods, but particularly rich or heavy foods may induce a sense of queasiness, sweating and diarrhoea (“dumping syndrome”).

Undergoing obesity surgery

Most people considering obesity surgery have lived with obesity most of their lives, and have endured cycles of dieting, weight loss and weight regain. Sadly there persists a stigma in our society that obesity is self-inflicted. In reality, obesity is a complex chronic disease involving genetics, environment, hormones, upbringing, cultural background, socioeconomic status and psychological distress.

Undergoing obesity surgery is a big step for most people, it is certainly not “cheating” nor “the easy way out”. On the contrary, an obesity surgery journey includes a comprehensive medical assessment, pre-surgery preparation with a special low calorie diet, months of restricted eating after surgery and then commitment to long term follow-up with dietitian input, vitamin supplements and regular blood tests.

It is a challenging and ultimately very rewarding journey for most patients, leading to a prolonged, healthier life.

Where to get help

• Your GP (doctor)
• NURSE-ON-CALL Tel. 1300 60 60 24 – for expert health information and advice (24 hours, 7 days)
• Australian & New Zealand Metabolic and Obesity Surgery Society