Source: Exercise New Zealand
As New Zealand joins a growing number of countries offering GLP-1 weight loss injections (such as Ozempic and Wegovy), Exercise New Zealand is urging Kiwis and health professionals to understand the hidden health risks that could come with this quick-fix solution, particularly the alarming loss of muscle mass, and long term increased health costs.
“People are losing fat, yes, but they’re also losing muscle, which is vital for long-term health,” said Richard Beddie, CEO of Exercise New Zealand.
“This isn’t just about aesthetics. It’s about strength, mobility, immunity, and long-term cardiovascular health.”
“A more holistic approach to weight loss is urgently needed, especially for those using GLP-1 medications.”
“Protecting muscle through strength training, high-protein diets, and regular monitoring should be a core part of any weight loss plan.”
GLP-1 drugs mimic a gut hormone that helps regulate blood sugar and appetite, helping people shed weight quickly. While effective in controlling obesity and diabetes, new research shows a significant downside: rapid loss of lean muscle mass, even in young users. Recent studies suggest that GLP-1 receptor agonists (GLP-1 RAs) effectively reduce weight by suppressing appetite, however up to 60% of weight lost can be of lean muscle mass, not fat.
Sarcopenia: not just for the elderly anymore
Sarcopenia, or muscle loss, is typically associated with aging, but emerging research shows that weight loss drugs like GLP-1 receptor agonists can cause similar effects in people of all ages. Without proper exercise and nutrition, even younger users risk losing significant muscle mass, accelerating age-related decline.
Low muscle mass has been linked to increased risks of heart disease, insulin resistance, falls, and early frailty. Reduced strength can also limit mobility and quality of life. Entering adulthood with poor muscle reserves makes later-life decline faster and harder to reverse.
The economic consequences for New Zealand are just as serious. As more New Zealanders struggle with frailty and reduced mobility, healthcare costs will rise. While local data is limited, UK research adjusted for New Zealand’s healthcare system suggests sarcopenia could cost households an additional $4,000 to $6,000 per year, driven by hospitalisations, rehabilitation, and long-term care. Frailty alone has been shown to increase healthcare costs by up to 56% annually.
For younger people on GLP-1 medications, unchecked muscle loss could result in long-term health and financial burdens. That’s why protecting muscle through strength training, high-protein diets, and regular monitoring should be a core part of any weight loss plan.
What should be done?
Research based evidence has shown that users on GLP-1 should adopt a strength-based training routine alongside adequate protein intake.
It’s well known that weight loss via dieting often results in the ‘yo-yo effect’, with around 80% of those who lose weight gaining it back again in the long term.
Concerningly, the latest research shows this to be the case with GLP-1 drugs too, with a meta-analysis by Oxford University showing almost all GLP-1 participants gain their weight back within 12 months.
One of the benefits of pairing strength training with these drugs is that it introduces a behaviour change element, which helps keep the weight off long term. A Finnish study showed that those who incorporated exercise at the same time as GLP-1 had far more effective long term weight loss than those on the drug alone.
ExerciseNZ is urging healthcare providers, patients, and policymakers to adopt the following evidence-based measures:
Incorporate resistance training into all weight loss plans: Engage in full-body strength training at least twice a week, focusing on major muscle groups. Resistance exercise is scientifically proven to preserve and rebuild muscle mass, especially during calorie restriction or pharmacological weight loss.
Monitor muscle mass, not just the number on the scale: Weight loss that includes too much lean mass can increase health risks. Clinicians should track body composition regularly, using tools like bioimpedance or DEXA scans, to ensure muscle is maintained or improved throughout treatment.
Prioritise high-protein nutrition and supervised programmes: Adequate protein intake (1.2–1.6g per kg of body weight) is essential to support muscle maintenance. Structured programmes combining nutrition education and exercise supervision provide the safest and most effective outcomes.
“It’s clear that drugs, just like dieting, seldom work by themselves in the long term,” says Beddie. “Weight loss shouldn’t come at the cost of your strength, vitality, and future health.” He adds, “GLP-1 drugs should come with a warning label: Must be used in conjunction with a strength based exercise routine.”
