As New Zealand joins a growing number of countries offering GLP-1 weight-loss injections — such as Ozempic and Wegovy — authorities are sounding the alarm about the hidden health risks that may accompany these seemingly rapid-fix solutions. In particular, Exercise New Zealand is urging Kiwis and health-care professionals to understand a lesser-disclosed danger: rapid loss of muscle mass, and the long-term implications this may hold for strength, mobility and overall health.

At Bay Surgery, while our primary focus is surgical interventions (gastric bypass and sleeve) for individuals with significant weight-related health issues, we believe it’s vital to highlight that any route to weight-loss needs to consider the whole person — not just the number on the scale.

The Rise of GLP-1 Medications and What They Do

GLP-1 receptor agonists (GLP-1 RAs) mimic a gut hormone known as GLP-1, which regulates blood sugar and appetite. This class of drugs supports rapid weight loss by curbing hunger signals and slowing gastric emptying — mechanisms that have made them an attractive tool in obesity and diabetes treatment.

However, as Exercise NZ notes: while fat loss is indeed happening, for many users this comes at the cost of lean muscle mass — loss of muscle that underpins strength, metabolism, immune function and long-term resilience.

Why Muscle Loss Matters

Emerging research suggests that in some cases up to 60% of weight lost on GLP-1 medications may actually be lean muscle rather than fat — a startling figure given the implications.

The phenomenon of muscle loss, or sarcopenia, is traditionally associated with aging — but is now becoming a concern across age groups in the context of rapid pharmacological weight loss. Without adequate muscle reserves, individuals face increased risk of insulin resistance, cardiovascular problems, falls, early frailty and reduced quality of life.

What It Means in a Surgical Context at Bay Surgery

At Bay Surgery, our patients often come to us after prolonged struggles with obesity and its comorbidities. Gastric bypass and gastric sleeve procedures are powerful tools — but no matter which weight-loss path you take — pharmacological, surgical or lifestyle-based — preserving muscle must be part of the conversation.

Here are important considerations:

Surgery vs medication: While GLP-1 drugs may help many lose weight, if muscle loss is ignored, the long-term health risks remain. Surgical options provide structured reduction of stomach volume or absorption change, but still require strong lifestyle support.

Post-operative muscle health: After bariatric surgery, muscle preservation is critical. Patients must engage in resistance training, and adopt sufficient protein intake and physical activity to maintain or build muscle — preventing frailty or metabolic slow-down.

Informed decision-making: Patients considering GLP-1 medications should be fully informed of the potential for muscle loss, and ideally receive guidance on strength training, nutrition and monitoring. At Bay Surgery we emphasise these elements in our multidisciplinary support programmes.

Evidence-Based Recommendations from Exercise NZ

Exercise NZ is urging healthcare providers, patients and policymakers to adopt these evidence-based measures:

1. Incorporate resistance training into all weight-loss plans

Engage in full-body strength training at least twice weekly, focusing on major muscle groups. Resistance exercise is scientifically proven to preserve and rebuild muscle mass, especially during times of calorie restriction or pharmacological weight loss.

2. 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 such as bioimpedance or DEXA scans — to ensure muscle is maintained or improved throughout treatment.

3. Prioritise high-protein nutrition and supervised programmes

Adequate protein intake (1.2–1.6 g 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.

4. Lifestyle integration

Strength training and education about long-term healthy behaviours are key to avoiding the common “yo-yo” effect — research shows that, even with GLP-1 medications, most participants regain weight within 12 months if lifestyle change is not consolidated.

What You Can Do If You’re Considering Weight Loss Drugs or Surgery

• If you’re exploring GLP-1 medication or surgical options for weight loss, ask your provider “How will muscle mass be monitored and preserved?”

• Work alongside a dietitian and exercise physiologist to design a strength-based training plan and ensure adequate protein intake.

• Ensure your body-composition is assessed before, during and after treatment — not just weight and BMI.

• At Bay Surgery, we offer comprehensive support as part of our service in Tauranga, including nutritional guidance, exercise planning and long-term follow-up to safeguard muscle, strength and health.

In Summary

While rapid weight loss through GLP-1 medications or surgical routes may provide exciting short-term results, the deeper truth revealed by Exercise NZ is this: losing muscle along with fat undermines long-term health. Strength, mobility, immunity and cardiovascular resilience all depend on preserving lean mass. As Richard Beddie observed:

At Bay Surgery in Tauranga, we encourage patients to take a holistic view: Get the tools you need to lose weight, yes—but do so in a way that builds and protects strength, vitality and a healthier future.

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