How to Preserve Muscle During Weight-Loss | A Guide for GLP-1 Users and Post-op Patients

A few weeks after your bariatric surgery or once you’ve settled into your GLP-1 routine, you may notice changes in how your clothes fit and how your body feels.

‘Weight loss is not only about the number on the scale,’ says Dr Jason Winnett, Melbourne-based bariatric surgeon, ‘but also about preserving muscle and supporting overall health.’

In this article, Dr Winnett explains why preserving muscle is an important part of high-quality weight loss and outlines a simple plan to support it.

Why is preserving muscle an important part of high-quality weight loss?

An article published in the peer-reviewed journal Metabolism reported that more than 25% of the total weight lost from both surgery and medications like GLP-1s typically comes from fat-free mass, including skeletal muscle.

‘Skeletal muscle is the muscle that moves your body and is attached to your bones by tendons,’ says Dr Winnett. ‘The simplest example is the muscle in your arms or legs that helps you walk, lift, and bend.’

It’s a part of weight loss that a lot of patients overlook and can impair metabolic health while raising the risk of a condition called sarcopenic obesity.

‘Sarcopenic obesity is what happens when you lose weight, but you also lose too much muscle along the way; you end up carrying excess fat while becoming weaker on the inside.’

A 2025 article published in Clinical Nutrition & Metabolic Care points to several key downsides of losing muscle during weight loss:

Weaker bones and higher fracture risk.
A bigger impact on those with less muscle to spare; the effects hit hardest in people who start with low muscle mass, especially older adults.
Frailty risk from weight cycling: because stopping a GLP-1 often leads to regain, repeated cycles of losing and regaining weight are linked to greater muscle loss and frailty over time.

That’s why preserving muscle during weight loss is the difference between simply ‘losing weight’ and achieving high-quality weight loss.

Preserving muscle for GLP-1 users and bariatric surgery patients: a simple, two-step plan

Protecting muscle during weight loss doesn’t require a complicated routine.

Combining adequate protein intake with resistance training may help support better outcomes.

An article published in Nutrients found that in patients 2-7 years after surgery, resistance training (irrespective of protein supplementation) increased fat-free mass by about 1.5 kg and skeletal muscle mass by about 0.9 kg, while the control group showed a slight decline.

The same principle applies beyond bariatric surgery.

For GLP-1 users, adding exercise to weight-loss efforts may also provide additional benefits.

A recent JAMA study of 195 participants found that exercise helped preserve bone health during weight loss.

Here are two key steps to preserving muscle while using weight-loss medications.

1. Move with purpose

Sarah Pizzi, Exercise and Lifestyle Consultant at Winnett Specialist Group, says: ‘After bariatric surgery, and for people using GLP-1 medications, resistance training is one of the best ways to give your body the message that muscle still matters.

‘It doesn’t need to be complicated. Bodyweight exercises, resistance bands and light weights can all be a great place to start.’

For post-op bariatric surgery patients:

Day 1: Start by getting out of bed and walking to a chair, then back again if able.
Day 2–7: Begin short walks throughout the day, about 2 minutes at a time, up to 10 times daily.
Week 2: Increase walking to 20–60 minutes a day, five days a week. This can be broken into smaller sessions. If approved, you may also begin light weights, such as 1–2 kg, twice a week.
Week 3: Once the incisions have healed, swimming may be possible. Driving can usually resume if you are pain-free and no longer taking strong pain medication.
Week 4: Sexual activity can usually be resumed, although some patients may be ready sooner if they have no abdominal pain.
Week 6: More demanding movements, such as squats and lunges, may be added.
Week 12: A return to competitive sport is often possible, depending on recovery and medical clearance.

Recovery timelines vary between patients and should always be individualised according to the surgical team’s advice.

For GLP-1 users:

Notice: Recovery timelines vary and should always follow your surgical team’s advice.

Step	Type of activity	Frequency & duration	Goal/benefit
1. Gradual movement	Brisk walking, light aerobic activity	Start with 10 minutes per day, then build up to 150 minutes per week of moderate activity or 75 minutes per week of vigorous activity	Improves aerobic fitness and reduces fatigue
2. Resistance training	Resistance bands, weights, or bodyweight exercises such as squats and lunges	2–3 sessions per week, 20–30 minutes each, for a total of 60–90 minutes per week	Preserves lean body mass, bone density, and muscle strength
3. Maintenance	Combined aerobic and resistance training	30–60 minutes of aerobic activity daily, plus 2–3 resistance sessions per week	Supports long-term weight control, metabolic health, and function
Additional focus	Balance and mobility work	Integrated into the weekly routine, especially for older adults	Helps prevent sarcopenia and reduces fall risk

Source: GLP-1 agonists and exercise: the future of lifestyle prioritization

2. Make protein a priority

Ashleigh Gale, Dietitian at Winnett Specialist Group, says: ‘Protein is essential for recovery and for maintaining muscle during weight loss. After bariatric surgery, appetite is often lower, so it’s easy to fall short on protein without realising it.’

Ashleigh’s 5 simple protein tips:

Eat protein first. Build meals around protein before adding other foods.
Include protein at every meal and snack. Small, regular amounts add up over the day.
Choose high-protein foods. Good options include eggs, Greek yoghurt, cottage cheese, tofu, fish, chicken, lean meat and protein shakes.
Use protein snacks when appetite is low. Keep easy options on hand, such as yoghurt, boiled eggs, cottage cheese or a protein bar.
Make protein easier to absorb into your routine. Add protein powder to drinks, soups or porridge when needed.

Losing weight doesn’t have to mean losing muscle

Better outcomes may be achieved when weight loss is paired with habits that protect strength, function and bone health.

For bariatric surgery patients and GLP-1 users alike, that means making movement and protein part of the plan from the start.

At Winnett Specialist Group, our team, including Exercise and Lifestyle Consultant Sarah Pizzi and Dietitian Sarah Pizzi, provides holistic, individualised support before and after surgery, and while using GLP-1s.

Get in touch with us for tailored advice on how you can lose weight and achieve a healthy lifestyle while preserving muscle.

Reviewed April 2026 by Dr Jason Winnett

AHPRA Registration MED0001155541

This article provides general information only. Not medical advice. All procedures carry risks and results are individual. Consult your GP and a specialist surgeon or seek a second opinion before proceeding.