Several procedures exist. They differ in how they work, how much weight loss they typically produce, their effect on other conditions, and their nutritional consequences.
A note on mechanism: these procedures are not simply restrictive. They alter gut hormone signalling in ways that reduce appetite and improve insulin sensitivity — which is why metabolic improvement, particularly in type 2 diabetes, often appears before significant weight loss.
Sleeve gastrectomy
The most commonly performed procedure in Australia. A large portion of the stomach is removed, leaving a narrow tube.
Reduces capacity and alters hormonal signalling. No rerouting of the intestine, so nutritional consequences are somewhat less extensive than bypass — though supplementation is still required. Reflux can worsen in some people, and is a consideration if you already have it.
Roux-en-Y gastric bypass
A small stomach pouch is created and connected to a section of small intestine further down, bypassing part of the digestive tract.
Produces substantial weight loss and strong effects on type 2 diabetes. Nutritional consequences are greater because absorption is altered — lifelong supplementation and monitoring are essential. Often preferred where significant reflux is present.
One-anastomosis gastric bypass
A variation using a single connection. Similar principles; the balance of advantages differs and is a discussion for your surgeon.
Adjustable gastric band
An inflatable band placed around the upper stomach. Use has declined substantially due to lower long-term weight loss and higher rates of reoperation and band-related complications. Still relevant to people who have one and are considering revision.
Endoscopic options
Including intragastric balloons and endoscopic sleeve procedures. Less invasive and reversible, with generally smaller weight loss. Sometimes used where surgery isn't suitable or wanted.
How the choice is made
Depends on your BMI, related conditions — particularly diabetes and reflux — previous surgery, nutritional risk, and preference after a full discussion of trade-offs. There isn't a single best procedure, and surgeons differ in what they favour. A second opinion is entirely reasonable.
Related: Eligibility · Recovery and nutrition · Non-surgical options Next: Find a bariatric service →
Educational information only. Not a substitute for medical advice — speak to a qualified health practitioner about your circumstances.