Weight Loss Surgery Options
Every operation has its own pros and cons. The right one for you depends on your health, medical and surgical history, and what you hope surgery will do for you. You and Dr Lourensz decide together after a full assessment. The assessment usually includes a gastroscopy, to check for signs of reflux, a hiatus hernia or anything else that affects which operation suits you best.
Did You Know?
More than 21,000 weight loss surgery procedures were performed in Australia in 2023. The gastric sleeve was the most common, making up about 8 in 10 (79.8%) first-time operations.
Source: Monash University summary of the Bariatric Surgery Registry 2023 Annual Report
| Consideration | Gastric sleeve | Roux-en-Y bypass | One anastomosis bypass |
|---|---|---|---|
| How it works | Part of the stomach is removed; the bowel is not rerouted. | A small stomach pouch and two bowel joins reroute food. | A stomach pouch and one bowel join reroute food. |
| Reflux | Reflux can start or worsen. | Often favoured for significant reflux; diverts bile away from the pouch. | Bile reflux is a recognised risk and needs careful consideration. |
| Nutritional follow-up | Supplements and regular blood tests. | Lifelong supplements and regular blood tests; reduced absorption. | Lifelong supplements and regular blood tests; reduced absorption depends partly on bowel length bypassed. |
| Pregnancy plans | Pregnancy is not recommended for 1 to 2 years after any weight loss operation. Discuss plans before surgery. | ||
| Oral contraception | Discuss reliable contraception with your GP. | The pill may be absorbed unreliably, affecting efficacy. Non-oral contraception is recommended. | |
Gastric Sleeve (Sleeve Gastrectomy)
This is a keyhole (laparoscopic) operation. About three quarters of the stomach is removed, leaving a narrow tube a similar size and shape to a banana. You feel full sooner, and the hormones that drive hunger change. A sleeve suits most people, but may not be the right choice if reflux is a major problem or you have a large hiatus hernia. It has a lower risk of early complications than a bypass and doesn't reroute the bowel, but reflux is more common. It is very effective for most people. It also leaves further surgical options down the track: a gastric sleeve may be converted to a gastric bypass when appropriate; revision after a bypass is more complex. More about the Gastric Sleeve
Gastric Bypass
A small pouch is made at the top of the stomach and joined to the small bowel, so food bypasses most of the stomach and the first part of the bowel. There are two main types: the Roux-en-Y gastric bypass and the One Anastomosis gastric bypass. In a large randomised trial (YOMEGA, Lancet 2019), weight loss two years after a One Anastomosis gastric bypass was similar to a Roux-en-Y gastric bypass. It involves one less join (anastomosis). A Roux-en-Y gastric bypass can help control acid reflux and diverts bile away from the stomach pouch, so it is often favoured for significant reflux. OAGB can cause bile reflux and requires careful selection. A One Anastomosis gastric bypass can be revised to a Roux-en-Y gastric bypass if required. Dr Lourensz performs both. A bypass is very effective, but has a different side effect profile to a gastric sleeve. You will need vitamin and mineral supplements for life, and regular blood tests. More about the Gastric Bypass
Lap Band Management, Removal and Revision
Dr Lourensz looks after existing gastric bands that have been placed by other surgeons, and is happy to perform adjustments when required. If your band is causing reflux, vomiting or trouble eating, or has stopped helping with your weight, it can be removed or converted to a sleeve or bypass, either in one operation or in two operations a few months apart. About Lap Band Management
Revisional Surgery
For people who have had a sleeve or bypass and now have reflux, trouble eating or weight regain. Revision is more complex than a first operation and starts with a careful assessment.
Risks
Every weight loss operation carries risk, including bleeding, leaks, infection, blood clots, nutritional deficiencies and the need for further surgery. Dr Lourensz will go through your own risks in detail at your appointment, and answer any questions you have.
Pregnancy and Contraception
Pregnancy is not recommended for 1 to 2 years after weight loss surgery, including both sleeves and bypasses. Discuss your plans before surgery.
After either type of gastric bypass, the oral contraceptive pill may be absorbed unreliably, which may affect its efficacy. Non-oral contraception is recommended. Discuss a suitable method with your GP.
After Surgery
You start on fluids, then progress through pureed and soft food before returning to a normal diet. You will need to take supplements, have regular blood tests, and see Dr Lourensz and Louise Becroft for follow-up. Weight loss surgery works best with long-term follow-up, and you stay with the same team for as long as you need. The Weight Loss Program page has the full pathway and costs.
Paying for Surgery
You receive a written estimate of all costs before surgery is booked. If you are paying yourself, you may be able to use some of your superannuation through the ATO's compassionate release scheme. See Using Your Superannuation for who is eligible and how to apply.
Reviewed by Dr Kaleb Lourensz · Last reviewed October 2026