Ozempic, Wegovy & Mounjaro: What You Need to Know Before Starting GLP-1s for Weight Loss
- Ciara Ryan
- Sep 11
- 7 min read
GLP-1 medications — names you’ll know like Ozempic, Wegovy, and Mounjaro — are a hot topic. Some call them miracle injections. Others worry about side effects.
Many are quietly wondering: is this the answer I’ve been waiting for?
The truth sits in the middle. These drugs can change lives, especially for people living with type 2 diabetes or struggling with obesity. They’re not a magic pill (or jab). What you eat, how you move, and the habits you build while taking them will shape how well they work long term and how likely you are to run into side effects.
In my experience, the people who approach GLP-1s as a chance to reset their relationship with food see the best outcomes — steadier energy, better blood sugar control, less “food noise,” and confidence that lasts.
In this article we explore how these medications work, the common side effects and hidden risks, what to eat while on them, and the one piece of advice I share with every client who walks through the door.
What is Ozempic used for — and how does Ozempic weight loss work?
Doctors prescribe Ozempic (semaglutide) primarily for type 2 diabetes because it helps regulate blood sugar and lowers cardiovascular risk. Its appetite-dampening effect also makes it useful for weight loss. Wegovy is the same active ingredient, licensed for obesity. Mounjaro (tirzepatide) is newer; it works on two gut hormones and shows even greater weight-loss potential in trials.
In plain language: these medicines mimic a gut hormone (GLP-1). They slow digestion, quiet hunger signals, turn down “food noise”, and support insulin release.
Research shows average Ozempic weight loss is about 10–15% of body weight over 12–18 months (Wilding et al., 2021, NEJM). Some people lose more, some less.
And remember — the numbers only tell part of the story. Energy, mood, and long-term health matter just as much.
Which is better: Ozempic, Wegovy or Mounjaro?
If you’re scanning the headlines, it can look like a race between brands. The reality is more practical:
Ozempic: prescribed for type 2 diabetes, but often used off-label for weight loss.
Wegovy: same active ingredient, licensed for obesity.
Mounjaro: newer, acts on GLP-1 and GIP hormones, with studies showing greater weight loss (around 20% of body weight in some cases, Jastreboff et al., 2022, NEJM).
Availability depends on where you live. In Ireland and the UK, supply can be patchy, and eligibility criteria are strict. There isn’t a simple answer to which one is “better” — the right choice depends on your health profile, goals, and what your doctor prescribes.
I should also note an oral GLP-1 called orforglipron is currently in late-stage trials. It’s a once-a-day tablet that’s shown weight loss of around 12–13% in studies so far. If all goes smoothly, it could be available for patients as early as 2026. For some, the idea of a tablet might feel a lot more doable than a weekly injection — though of course, it will come with its own set of pros and cons.
Common side effects and how to manage them
Most people notice some side effects, especially at the start:
Nausea: 70–80%
Constipation: 60–70%
Fatigue: 40–50%
Acid reflux: 30–40%
Vomiting: 20–30%(Jastreboff et al., 2022)
These symptoms often peak in the first two weeks, start to settle by week four, and for most, ease by months two or three.
We advise clients with the following simple tweaks to help:
Keep portions small — your stomach empties more slowly.
Drink water regularly.
Prioritise fibre-rich foods to ease constipation. (See How to manage constipation the natural way for more info).
Eat slowly, and stop when you feel comfortably full, not stuffed.
Side effects are common but manageable.
Support and guidance during this stage can make the difference between sticking with the medication or giving up early.
What about more serious side effects? You may have seen headlines about lawsuits or rare complications linked to GLP-1 medications including conditions affecting the digestive system, pancreas, vision and thyroid. These risks are uncommon, but they do exist — and they are closely monitored by health authorities. They are part of the reason why these drugs are only available on prescription. Your doctor will weigh up the risks and benefits before recommending them. If you’re thinking about starting, or you’re already on one and notice anything unusual or worrying, it’s always best to check in with your GP straight away.
Hidden risks you should be aware of
Muscle loss
It’s not just fat that disappears when the weight comes off. Studies show up to 39% of weight lost can be lean mass if protein and activity aren’t prioritised (Wilding et al., 2021). Muscle protects your metabolism, bones, and blood sugar. Lose too much, and it becomes harder to keep weight off later.
That’s why I stress with every client: prioritise protein at every meal and add strength-based exercise each week. Whether it’s weights, resistance bands, or bodyweight moves, protecting muscle now sets you up for long-term success.
Emotional triggers
GLP-1s turn down hunger, but they don’t erase the reasons people eat when they’re not hungry. Stress, boredom, or comfort — those patterns don’t vanish. If you don’t address them, old habits can resurface the minute the medication stops working as strongly.
Coming off the meds
The elephant in the room: what happens when you stop?
Research shows that without lifestyle change, weight regain is common. That’s not to say you shouldn’t take them long term — many do under medical advice. But what’s clear from studies, and from what I see in clinic, is that those who use this time to practise new food choices, movement, and stress management keep more of their progress — on or off the medication.
What should you eat on GLP-1s?
Here’s the rule of thumb: smaller portions, higher quality.
Protein: eggs, fish, beans, lentils, chicken, yoghurt — they protect muscle and keep you satisfied. If you need inspiration, this blog shares simple ways to get more protein into your day.
Colour: vegetables and fruit for vitamins, minerals, and fibre (also helps manage constipation).
Carbs: choose slow-release options like oats, brown rice, and root veg to keep energy steady.
Healthy fats: olive oil, nuts, seeds, oily fish — they add staying power and support hormones.
Think of your plate as prime real estate. Every forkful is an opportunity to fuel your body well — and yes, every bite counts.
“When you’re eating less, every bite counts more than ever. Choose wisely, and those bites can transform your energy, mood, and long-term health.”
Nutrition and movement go hand in hand
When appetite is reduced, it’s easy to under-eat or fill up on “empty” foods. Eating less doesn’t mean eating nutrient-poor food. Smaller portions make food quality even more important.
A packet of crisps will fill you up, but it won’t fuel you. Swap it for a bean and veggie salad with olive oil and seeds — and you’ve got a meal that supports muscle, gut health, and steady energy. (Greek Butter Beans is one of my weekly go-to's)!
Movement is just as important. Cardio helps your heart, but it’s strength-based exercise that protects muscle, bone, and metabolism so you keep the results you’re working for.
This is your chance to use smaller portions wisely. Every bite counts — and what you choose now can set you up for stronger muscles, steadier energy, and better long-term health.
Emotional and stress eating
GLP-1s often quieten food noise, but they don’t silence emotional eating. Some people find that once appetite is reduced, they’re faced with the real reasons they turned to food — comfort after a hard day, stress at work, or habits like “Friday takeaway.”
Working through these patterns is key to long-term success. A positive relationship with food is one of the best supports for health and happiness. (If stress eating feels familiar, you might find this article helpful).
That’s why tailored support matters. At Ciara Ryan Nutrition we match meals to your goals and your life so you get enough protein, fibre, and key nutrients without upsetting digestion. It’s about feeling well and building a sustainable long-term routine, not just weighing less.
Supporting your gut while on GLP-1s
Nausea, constipation, and reflux are the most common early complaints. Because GLP-1s slow digestion, gut support is key. Hydration, fibre, and gentle meal adjustments can reduce discomfort and help you stay consistent with treatment. Small tweaks often make a big difference here.
The bottom line
GLP-1s like Ozempic, Wegovy, and Mounjaro can be powerful tools — but they’re not the whole solution.
Used alongside good food, movement, and support, they can help you reset your relationship with food and open the door to lasting health. That’s where the long-term wins live — for weight, blood sugar, energy, and peace of mind.
So if you’re taking one now, or considering it, here’s my one piece of advice: make every bite count.
You don’t have to work it out on your own. With the right guidance, you can protect your health, feel energised, and build habits that stay with you for life.
Book a free 30-minute health review with us — we’ll talk about where you are now and where you’d like to be, no pressure, no jargon.
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Disclaimer: The information in this article is for educational purposes only. It is not intended as medical advice and should not replace consultation with your doctor or healthcare provider. Always follow the guidance of your prescribing physician regarding GLP-1 medications.
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