In the era of weight loss injections, how does someone choose what's right for them?

A/Prof Michael Talbot MBChB FRACS A/Prof Michael Talbot offers expert, comprehensive surgical care in Bariatric Surgery, Upper Gastrointestinal Surgery, Therapeutic Endoscopy/ERCP, Oesophageal Physiology and Reflux. As a specialist in both Bariatric and Upper GI surgery, he combines surgical precision with a strong focus on long-term health outcomes.

23rd June, 2025

People living with weight problems are aware of every new fad, trend or gimmick for weight loss and have often tried many of them to discover that they just don’t work. How can someone know if these new medications are legit or just another disappointment waiting to happen? 

If we remove the hype, stigma and judgement of people taking these medications, what we see are real stories of real people getting their weight and health under control - this is backed up by studies on the outcomes of many thousands of patients taking these medications over many years.  The medications are not perfect, they cause side effects in some people and not everyone finds they work for them, but for most, this will be the first ever truly effective weight loss treatment they have tried. 

How do we rate the effectiveness of obesity therapies?  

We measure weight loss and its durability. To do this we use the term percentage weight loss (%WL), which allows us to compare treatments when used on people of different sizes. 

• Diets + exercise + psychology + dietician = 3-5% weight loss. 1 in 10 lose more than 10%, most regain within 2 years, 1 in 20 patients maintain weight loss.  

 • Very Low Energy Diets (VLED) shakes/bars as meal replacements = 10-15% weight loss, with ½ maintaining >5% weight loss and ¼ maintaining >10% weight loss at 5 years. 

• Weekly injections of current GLP-1 agonist medications = 10-15% weight loss, with weight loss maintenance (rather than further weight loss) if the medication is maintained. Over 80% of patients stop medication within 2 years and >85% of the weight is regained, but some patients may be able to develop strategies to limit how much they regain. 

 • Sleeve gastrectomy = average 30% weight loss. 10% average weight regain by 5-10 years. 

 • Gastric Bypass = average 40% weight loss. 10% average weight regain by 5-10 years. 

So, what’s right for one person won’t be right for another, but knowing how much you need or want to lose can be a great guide. It also means that if you have attempted to lose weight, failing to get a great result from a diet doesn’t make you a failure, it just wasn’t the right choice for you. 

The good news is that these treatments can “stack” - a GLP-1 agonist + VLED + diet and exercise will work better than trying them separately; also, a GLP-1 agonist followed up with diet and exercise is better than a GLP-1 agonist alone. 

Bariatric surgery also gets additional benefit from the addition of extra treatments. We know that GLP-1 agonists, taken by those who have regained or fallen short of their goals after Sleeve or Bypass, can lead to an extra 10-12% weight loss, at a ½ dose and with less side effects than for patients with a normal stomach.

Obesity is a complex, chronic disease that deserves the same mindset as asthma, diabetes, cancer or heart disease. That means using evidence-based treatment, tailoring treatments to people based on their needs, and using all the tools in the toolbox.

This information is general in nature. Please see your GP or specialist to discuss your personal health needs.