GLP-1 medications, why do I still need to see a dietitian?

GLP-1 receptor agonists, the drug class that includes Ozempic, Wegovy, Mounjaro, and Saxenda, have really changed the way people are thinking about weight loss and weight management in Australia. There’s no denying that they work and for a lot of people they’re the first thing that has actually shifted the dial after years of trying.

Where I’m seeing people need guidance is surrounding what they’re eating while on them, and then helping support what they eat after they come off it, to make sure that the weight loss they’ve achieved isn’t just temporary, and that it sticks!

I’m Andrew, an APD running Thompson Community Dietitians across Logan, Ipswich and the Redlands. Here’s how a dietitian fits into the picture, and why Dietitians Australia has formally called for an APD to be alongside every weight loss drug prescription in this country.^[1]

Why the medications work and why it leads to problems

GLP-1s work by stimulating insulin release, suppressing glucagon (which lowers blood glucose), slowing how quickly the stomach empties, and acting directly on the appetite centres in the brain.^[2] Most people end up eating significantly less without thinking about it, which is why they work so well for weight loss and blood glucose management.

The flip side is that when total intake drops, the quality of what you eat matters a lot more. If you’re eating half as much food, every mouthful needs to pull its weight. A 2025 retrospective study of over 460,000 adults with type 2 diabetes newly prescribed GLP-1s found 22.4 per cent developed nutritional deficiencies within 12 months of starting the medication, with vitamin D the most common.^[3]

The muscle loss problem nobody talks about enough

Up to 40 per cent of the total weight people lose on these medications can come from lean tissue rather than fat.^[8] Looking at it from a different angle, the SURMOUNT-1 trial of tirzepatide showed participants lost 10.9 per cent of their starting lean mass over 72 weeks.^[4] That’s a real hit, particularly for older adults and anyone who weren’t carrying much muscle to start with. Did you know that from age 50, you lose around 1 to 2 per cent of your muscle mass each year, with strength dropping by about 1.5 per cent per year between ages 50 and 60, then 3 per cent per year after that?^[5] So you can imagine a 65 year old getting onto these drugs can risk sarcopenia quite quickly!

Muscle isn’t just about how you look. It’s metabolically active tissue that protects you from frailty, drives insulin sensitivity,^[6] and keeps your metabolism ticking. Losing it means a higher chance of regaining weight as fat once you stop the medication. The STEP-1 extension trial showed participants regained around two-thirds of their initial weight loss within a year of stopping semaglutide.^[7]

The two things that protect muscle during weight loss are adequate protein and resistance training. The joint advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association and The Obesity Society recommends at least 1.2 grams of protein per kilogram of body weight per day for people on GLP-1 therapy.^[8] In clinical practice during active weight loss, that target often pushes up closer to 1.6 g/kg to better preserve muscle. The Australian Dietary Guidelines via Eat for Health recommend 0.84 g/kg for the general adult population,^[9] so we’re talking about nearly double the baseline for most people. Reaching that high protein goal while your appetite is being massively suppressed really requires planning, and I find assistance!

Eating well when your appetite is gone

When you’ve gone from eating 3 large meals a day to barely being able to manage 1 to 2, the food we eat has to do some more heavy lifting. Some strategies I look for with my clients are:

Breakfast, overnight oats are hard to beat. Half a cup of rolled oats, three quarters of a cup of Greek yogurt, a tablespoon of chia seeds, a scoop of protein powder and a splash of milk, left in the fridge overnight, topped with berries in the morning. That’s around 30 to 35 grams of protein in a small jar, more than a lot of people manage in a whole day on a GLP-1. This can even be split up into 2 smaller meals to allow for the early satiety when eating.

For lunch, cottage cheese on sourdough toast with sliced tomato, avocado and cracked black pepper is one I recommend constantly. Easy on the stomach when you’re feeling queasy, and a half cup of cottage cheese gives you 12 to 15 grams of protein. Add a boiled egg on the side or some tinned tuna and you’re at 20 grams without it feeling heavy.

For dinner, the formula is simple, a palm-sized portion of lean protein (chicken thigh, salmon, lean mince, tofu, prawns) with whatever vegetables you can manage. Stir-fries work well because the volume is mostly veg. When eating, prioritise eating your protein portion first!

For snacks, think Greek yogurt with honey, hard boiled eggs, edamame, cheese with seed crackers, or tinned fish are my go to’s.

The pattern is the same across all of them. Concentrated protein, smaller volume, easy to eat when food doesn’t appeal.

Side effects that respond well to nutrition tweaks

Nausea, reflux, constipation, early fullness and food aversion are all common, and the published recommendations for managing GI symptoms on GLP-1s show most of them improve with the right adjustments.^[10] Smaller meals, prioritising protein and fluids first, easing back on fats during dose-titration, and being thoughtful about timing all make a difference. Most of these symptoms can be managed with nutrition adjustments inside a couple of weeks, before the point of needing to stop the medication.

What happens when you stop

Without a structured nutrition plan and behaviour change work, most people regain a significant portion of the weight within a year of stopping, which is why Dietitians Australia recommends nutritional counselling before, during and after the medication.^[1] The drug suppresses appetite, but it doesn’t teach you anything.

I always inform my clients as I get asked frequently what my thoughts are on these medications. They’re a great tool, but if we’re not addressing the reason behind the pattern old patterns will simply return. Working with a dietitian throughout means you’re building eating patterns and cooking confidence that hold up after the script ceases.

As with everything, my aim is to discharge you with skills to maintain your goals on your own.

Body composition is the better measurement

The bathroom scale can be actively misleading on a GLP-1. You might lose six kilos and be thrilled, but if a large portion of that is muscle, you’ve gone backwards.

InBody scans (a type of bioelectrical impedance) are quick, non-invasive, and good for tracking trends over time. DEXA scans (dual-energy X-ray absorptiometry) are the reference standard for body composition assessment,^[11] giving you a precise breakdown of fat mass, lean mass, bone density and visceral fat. For long-term GLP-1 clients, a baseline plus a follow-up every three to six months is genuinely useful.

I’m building referral pathways with local body composition providers across Logan, Ipswich and the Redlands so my clients can get scanned, send me the results, and we can adjust the plan. Lean mass dropping faster than fat mass means we ramp up protein, push resistance training, or talk to the prescriber about dose. The scale just can’t give you that picture.

How funding works for this

Most of my GLP-1 clients access dietetics through Medicare Chronic Disease Management plans (sometimes called a care plan) which give you up to five subsidised allied health visits per year.^[12] For DVA Gold card holders, there are no out of pocket costs for getting started, we just need a referral from your GP.

If you’re not sure what you’re eligible for, give me a call on 07 5616 6549 and I’ll talk you through it. No obligations.

The short version

GLP-1 medications work best when they’re part of a bigger plan. A dietitian’s job is to make sure you’re losing the right kind of weight, getting enough of what you need, managing the side effects, and building habits that outlast the prescription.

Taking new clients across Logan, Ipswich and the Redlands right now with no waitlist. Telehealth, home visits, and clinic locations coming soon. Send me a message at info@thompsondietetics.com.au or give me a call to get started.

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References

1. Dietitians Australia. National plea to place dietitians alongside all weight loss drug prescriptions.
2. Collins L, Costello RA. Glucagon-Like Peptide-1 Receptor Agonists. StatPearls, NCBI Bookshelf.
3. Pawar A, et al. Nutritional deficiencies and muscle loss in adults with type 2 diabetes using GLP-1 receptor agonists, a retrospective observational study (2025).
4. Look M, et al. Body composition changes during weight reduction with tirzepatide in the SURMOUNT-1 study, Diabetes Obesity and Metabolism (2025).
5. von Haehling S, Morley JE, Anker SD. An overview of sarcopenia, facts and numbers on prevalence and clinical impact (2010).
6. Srikanthan P, Karlamangla AS. Relative muscle mass is inversely associated with insulin resistance and prediabetes (2011).
7. Wilding JPH, et al. Weight regain and cardiometabolic effects after withdrawal of semaglutide, the STEP-1 trial extension, Diabetes Obesity and Metabolism (2022).
8. American College of Lifestyle Medicine, American Society for Nutrition, Obesity Medicine Association, The Obesity Society. Nutritional priorities to support GLP-1 therapy for obesity, joint advisory, American Journal of Clinical Nutrition (2025).
9. National Health and Medical Research Council. Australian Dietary Guidelines, protein nutrient reference values, Eat for Health.
10. Camilleri M, Lupianez-Merly C. Dietary recommendations for the management of gastrointestinal symptoms in patients treated with GLP-1 receptor agonists.
11. Nutritional priorities to support GLP-1 therapy for obesity, PMC version covering DEXA as the reference standard for body composition assessment.
12. Australian Government, Department of Health and Aged Care. Chronic Disease Management Plan.

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Image credits: Overnight oats photo by Nervy8924 (CC BY-SA 4.0), InBody body composition analyser photo by Longevity Medical Institute (CC BY 4.0), both via Wikimedia Commons. Hero salmon meal and high-protein toast images by Casey Lee and Joseph Gonzalez respectively, released into the public domain (CC0) via Unsplash.