GLP-1 Medications and Nutrition: How to Support Your Body and Make It Last

Over the past couple of years I have noticed more and more of my weight loss clients arriving already on a GLP-1 medication — Ozempic, Wegovy, Mounjaro. They have made that decision with their doctor, and they are coming to me for the nutritional support to make it work as well as possible.

GLP-1 is a tool in the toolkit. For many people it helps shift things that haven't shifted otherwise — despite the effort, despite the discipline, despite doing a lot of things right.

As a practitioner, my role when working with clients on GLP-1 medications is to support nutrient and vitamin absorption, prevent muscle breakdown, and help clients reach their weight loss goals successfully — whilst addressing the lifestyle and meal composition tweaks that will make those results last.

What GLP-1 Medications Actually Do

GLP-1 (glucagon-like peptide-1) receptor agonists work by mimicking a naturally occurring hormone that regulates appetite, slows gastric emptying, and improves blood sugar control (Drucker, 2024). In simple terms: you feel full sooner, you stay full longer, and your appetite is significantly reduced.

And that is exactly where nutrition comes in.

Looking After Your Muscle

When you lose weight — through any means — you lose a combination of fat mass and lean mass. Lean mass is everything in your body that is not fat — primarily muscle, but also water and connective tissue.

So in the early stages of GLP-1 therapy, some of what the scale reflects is simply fluid and glycogen loss, not muscle. But gradually this is shifting. Research consistently shows that actual muscle loss does occur alongside fat loss over time, with studies suggesting lean mass can account for between 25% and 45% of total weight lost depending on the individual and the medication (Neeland et al., 2024; Tinsley & Heymsfield, 2024). Therefore protecting muscle deserves active attention throughout the process.

Unlike fat loss, muscle loss carries real consequences: a reduced metabolic rate, reduced strength, increased fatigue, and greater risk of injury down the line. Your metabolic rate — sometimes called your basal metabolic rate or BMR — is essentially how many calories your body burns at complete rest, just to keep you alive and functioning. Muscle is metabolically active tissue, meaning it burns calories even when you are doing nothing. The more of it you have, the higher your resting calorie burn. Lose muscle, and that baseline drops. I wrote about this in more detail in this post → — worth a read if you want to understand why metabolic rate matters so much beyond just weight loss.

In my practice, I have observed that even clients doing strength training twice a week see a slight reduction in muscle mass in the early stages. This is can be temporary. With consistent training and the right nutritional support, the body adapts, muscle stabilises, and fat continues to reduce. The direction of travel matters more than any single data point.

I encourage clients to shift focus away from the scale and toward body composition. A basic body composition scale — reliable ones are available for around €100 — gives you a breakdown of fat mass versus lean mass. That information is far more useful than weight alone. It tells you whether you are losing fat or muscle, and it allows us to course-correct early if needed.

Strength Training Is the Foundation

If there is one thing I would encourage every client on a GLP-1 to prioritise, it is this: lift weights. Not to burn calories — that is not the point. But to send a clear signal to your body that your muscle is needed, and to counteract the lean mass loss that accompanies significant caloric reduction. Research consistently shows that resistance training combined with adequate protein is the most effective strategy for preserving muscle during GLP-1 therapy — one prospective study found that clients who followed structured resistance training and protein guidance alongside their medication lost around 13% of body weight but only 3% of muscle mass (Peralta-Reich, 2025).

Two sessions per week is a realistic and effective minimum. Three is better.

Nutrition: Quality Over Quantity

With appetite significantly suppressed, every bite counts more than ever. This is not the time to fill a reduced intake with low-nutrient foods. The focus shifts entirely to nutrient density — getting the most nutritional value from smaller amounts of food.

Reduce portions if you need to — but never reduce food quality. Smaller plates, yes. But those smaller plates should be filled with vegetables, quality protein, and whole foods.

Protein is your priority. I recommend a minimum of 25g of protein per meal. This is key for muscle preservation. When appetite is low it can feel like a lot — but it is very achievable, and it does not have to mean a chicken breast every time. Think of a simple salad: one egg (6g), a small handful of chickpeas and edamame — about 50g of each (10g combined), 2 tablespoons of hemp seeds (7g), a small amount of feta (5g), a base of quinoa or brown rice, and then cherry tomatoes, olives, and whatever greens you enjoy. That is around 28g of protein in a light, colourful, plant-forward bowl — with the grains and vegetables adding fibre, healthy fats, and keeping the meal satisfying without volume. Build your plate around protein first, then fill everything else in around it.

Fibre matters — and it is underrated in this conversation. GLP-1 medications slow gastric emptying, which can cause constipation and digestive discomfort in up to one third of people taking them (Gorgojo-Martínez et al., 2022). Gradually increasing fibre intake through vegetables, legumes, whole grains, and fruit — alongside generous hydration — is one of the most effective dietary strategies for managing these symptoms (Bioletto et al., 2024). The recommended daily fibre intake in the UK and across Europe is 25–30g per day — most people are nowhere near that. The key word is gradually. Adding too much too quickly is a reliable way to spend the day uncomfortable. Start by adding one extra portion of vegetables or legumes per day, increase your water intake alongside it, and build from there over two to three weeks.

Micronutrient gaps are a real risk. When overall food intake drops significantly, so does your intake of vitamins and minerals. Iron, B vitamins, zinc, magnesium, and vitamin D are the ones I monitor most closely with clients. To get a clear picture of where you actually stand, I often recommend either a Metabolomix test or a blood panel — because guessing at what to supplement is rarely the most effective approach.

Here is something that often surprises people: when you are actively losing fat, your body's nutritional needs actually increase. The liver is working harder than usual to process and clear stored fat — and it needs the right nutrients to do that job efficiently. Think of it like making sure the door is open before you try to take the rubbish out. If the key micronutrients are not there, that clearance process slows down, regardless of how well everything else is going.

One nutrient that deserves particular attention during weight loss is choline. Choline plays a central role in fat metabolism in the liver — it helps package and export fat so it does not accumulate — and deficiency can impair that process at precisely the moment you need it most (Sherriff et al., 2016). Good food sources include eggs, but when overall intake is reduced, a targeted supplement may be worth considering alongside your nutrition plan.

Making It Last

What you build nutritionally while you are on a GLP-1 is just as important as the medication itself. The habits around food quality, the relationship with strength training, the shift in how you measure progress — these are what carry you forward and help the results hold.

The medication is the tool. Nutrition and movement are the strategy. And having the right support around both makes all the difference.

If you are on a GLP-1 medication and want support building a plan that protects your muscle, manages your symptoms, and sets you up for lasting results, this is exactly the work we do together in a 1:1 consultation.

Book your free discovery call here →

Your journey to wellness starts now.

Karelle

Functional Nutrition Therapist (BANT, CNHC)

Proud winner of the Health & Wellness Award – Algarve Business Awards 2025

References

• Drucker DJ. Efficacy and safety of GLP-1 medicines for type 2 diabetes and obesity. Diabetes Care. 2024.

• Veronese N et al. Effect of glucagon-like peptide-1 receptor agonists and co-agonists on body composition: systematic review and network meta-analysis. Metabolism. 2024.

• Neeland IJ et al. Changes in lean body mass with glucagon-like peptide-1-based therapies and mitigation strategies. Diabetes Obes Metab. 2024.

• Tinsley GM, Heymsfield SB. Fundamental body composition principles provide context for fat-free and skeletal muscle loss with GLP-1 RA treatments. J Endocr Soc. 2024.

• Bikou A et al. Muscle mass preservation strategies during GLP-1 receptor agonist therapy: a narrative review. J Clin Med. 2024.

• Peralta-Reich D. Resistance training and protein guidance preserves muscle during GLP-1 therapy: prospective 6-month study. Presented at ObesityWeek. 2025.

• Gorgojo-Martínez JJ et al. Clinical recommendations to manage gastrointestinal adverse events in patients treated with GLP-1 receptor agonists: a multidisciplinary expert consensus. J Clin Med. 2022.

• Bioletto F et al. Dietary recommendations for the management of gastrointestinal symptoms in patients treated with GLP-1 receptor agonists. Diabetes Metab Syndr Obes. 2024.

• Sherriff JL et al. Choline, its potential role in nonalcoholic fatty liver disease, and the case for human and bacterial genes. Adv Nutr. 2016.