Ozempic, Mounjaro, and Wegovy are reshaping the world of weight loss. These medications, known as GLP-1 receptor agonist medications, can lead to remarkable weight reductions, marking the start of a new era in obesity treatment. With all the hype, you’d be forgiven for thinking that the way you eat and move has been replaced with an injection. In reality, diet and lifestyle still matter… perhaps more than ever.
This post explores how these drugs work, who should or shouldn’t use them, what a healthy GLP-1 weight-loss diet really looks like… and why food still holds the power.
When you eat, your body naturally releases hormones that help you regulate your appetite and blood sugar. One of these is GLP-1 (glucagon-like peptide-1) which helps control your blood sugar, slows down how quickly food leaves your stomach, and tells your brain that you have had enough to eat (1).
GLP-1 medications mimic this natural hormone, meaning that when you take it you feel full sooner, feel less hungry between meals, and experience fewer cravings and steadier blood sugar levels.
Here are some of the currently available forms of GLP-1 medication:
So far, so scientific… but what does this actually mean for real people trying to lose weight?
In clinical studies such as the SURMOUNT-1 clinical trial, people taking tirzepatide for just over 18 months, alongside healthy lifestyle changes, lost an average of 20% of their body weight (2).
These results are impressive, but here is the crucial point… in these studies, weight loss drugs were combined with diet and lifestyle changes. These drugs are not designed to replace changes in nutrition and movement, they are meant to work with them. Without a change towards healthier behaviours, the benefits are smaller, the side-effects are harder to manage, and weight regain is common once the medication is stopped.
GLP-1 injections are tempting, especially when social media is full of dramatic before-and-after stories… but they’re by no means a quick fix and in the wrong hands they can even be dangerous.
These drugs are currently only suitable for those with clinical obesity and accompanying weight-related health problems, not for anyone who just wants to drop a few pounds. In addition, buying GLP-1 medications online or through unregulated sellers is risky as counterfeit or incorrectly dosed products are increasingly common.
Interestingly, many of the same pathways that GLP-1 medications target (improved blood sugar regulation, reduced inflammation, and steadier appetite hormones) can also be influenced naturally through diet. A whole-food, plant-based diet rich in fibre, polyphenols and resistant starch has been shown to boost natural GLP-1 secretion and improve insulin sensitivity, without the side-effects or cost.
If you think GLP-1 medication might be suitable for you, talk to your GP or a registered dietitian specialising in weight management.
GLP-1 weight loss medications are not suitable for people with:
It is really important to know that delayed stomach emptying increases the risk of aspiration during surgery, so anyone taking a GLP-1 must inform their surgical team before an operation. They can also reduce absorption of medications such as the contraceptive pill or oral HRT, so always discuss with your doctor or pharmacist before taking.
Unwanted side-effects can be unsettling at first, but most symptoms improve as your body adjusts, and simple dietary tweaks can make a huge difference.
Because of their impact on digestion, many people experience nausea, indigestion, reflux, constipation, diarrhoea, or bloating in the first few months of use. Some people also report fatigue, hair loss, or discomfort at the injection site.
More serious side-effects, although less common, can include pancreatitis, gallstones (due to rapid weight loss) or malnutrition if food intake becomes too restricted (3).
A recent international advisory from leading nutrition and obesity organisations highlights that GLP-1 therapy should always be paired with evidence-based nutrition and lifestyle support to preserve health and ensure lasting success (4).
Here are our top tips for nutrition on GLP-1 medication:
Preserving muscles
With a poor appetite, protecting your muscles matters more than ever. When you are losing weight, aim for around 1.2–1.6 g protein per kg of body weight per day to help preserve lean mass. So, if you weigh 70 kg, you will want to aim for 84 – 112 g of protein daily. Add 1-2 plant proteins to each meal, for example tofu, beans, lentils, seitan, soya chunks or mycoprotein.
Combine this with resistance exercise two to three times weekly, using equipment such as weights, resistance bands, or even heavy shopping! Consider creatine monohydrate (3–5 g/day) alongside training to support strength and fat-free mass.
Nutrient density
With smaller portions, micronutrient density becomes critical. Choose a variety of colourful plant foods and get clued up on where you can get your vitamin B12, iron, calcium, vitamin D, iodine and omega-3 fatty acids.
Digestion and gut health
To support digestion, prevent constipation and promote gut health, we want to eat plenty of fibre. Don’t skip your complex carbohydrates such as oats, brown rice, whole wheat pasta and wholemeal bread, and bulk out meals with extra vegetables with fruit for afters.
Hydration
To reduce dehydration and kidney strain, stick to non-alcoholic drinks with no added sugar such as water, herbal teas and decaffeinated tea and coffee.
Plant-forward eating
Putting plants at the forefront of every meal and snack will naturally keep nutrient-density and fibre content high. If you are already plant-based, aim for increased variety in the plants you choose.
Mindful eating
Chew well, pause between bites and eat slowly. Taking time to notice textures, flavours and fullness cues helps reconnect you with your body’s signals, which is something that can feel different while on GLP-1 medication. Mindful eating also supports better digestion, reduces overeating, and makes smaller meals feel more satisfying.
What to leave out
Diets high in red or processed meat are linked to inflammation and colon cancer, so a plant-forward approach offers long-term protection as well as short-term results.
A well-planned vegan or plant-forward plate naturally delivers high-fibre foods, quality plant proteins and phytonutrients that support gut health and appetite regulation – the perfect match for GLP-1 therapy.
Many unwanted side-effects can be managed with some simple nutrition and lifestyle tweaks. Here are some tips for some of the most common symptoms:
Nausea: limit intake of added fats such as oils and heavy sauces, snack on dry starchy foods such as crackers and toast, take regular small sips of fluids, and choose cold meals to limit cooking smells such as sandwiches, salads and wraps. Adding ginger or peppermint to meals and drinks can also help.
Constipation: build fibre gradually and aim for at least 2 litres of fluid per day (or enough to reach light straw coloured urine) as a baseline. Add kiwi and/or chia seeds with a snack or dessert and ensure daily movement.
Reflux: eat smaller, more frequent meals, sit upright at a table to eat, avoid lying down or manual labour for at least an hour after eating, limit intake of caffeine, chocolate and high-fat foods, and try propping the head of your bed slightly if symptoms persist (avoid extra pillows to lift head as this can make sleeping posture worse).
Bloating: chew food thoroughly, eat slowly, build in new foods gradually, and limit fizzy drinks or very high-fibre foods until your digestion adjusts. Gentle movement after meals, such as a short walk, can also ease discomfort. Try to engage in relaxing or joyful activities regularly.
Regular review is essential while using GLP-1 medication, particularly when experiencing a high symptom burden. Tracking strength, energy, and bowel habits gives a more complete picture of health than weight alone.
GLP-1s are being studied for broader health effects, including improved cardiovascular outcomes and reduced inflammation. Early research hints at possible roles in Alzheimer’s and addiction treatment, though these are still experimental.
GLP-1s change the quantity of food you want to eat, but it is diet that determines how well you feel. Without focusing on food quality whilst taking GLP-1 weight loss drugs, we risk nutrient deficiencies, muscle loss, and poor long-term health. These medications can be a powerful tool, but they are not the whole solution. A thoughtfully designed GLP-1 weight-loss diet is what transforms short-term pharmacology into lasting metabolic health.
Because these medicines blunt natural hunger cues, it can take time to relearn how to recognise true hunger, satisfaction, and emotional triggers. Behavioural support or mindful-eating coaching can make this transition easier and safer.
If you’re using or considering a GLP-1 medications, here are the habits that make all the difference:
If you’d like to learn how to lose weight confidently on a plant-based diet, with or without medication, join my free masterclass: The 3 Secrets to Banish Cravings & Lose Weight on a Plant-Based Diet.
In just 50 minutes, you’ll discover how to manage cravings naturally and build habits that actually last, so you can stop relying on willpower and start feeling in control again.
It’s the perfect next step if you’re curious about GLP-1s but want to understand how nutrition can do the heavy lifting first.
And remember, GLP-1 therapy should be stigma-free, person-centred and equitable… they are a tool, not a shortcut or a moral choice.
If you want more from me, sign up to the Rosemary Nutrition mailing list. You also can contact me directly at rosie@rosemarynutrition.co.uk or follow me on Instagram at @plantdietitianrosie.
Plus if you’re interested… don’t forget to join one of our popular upcoming FREE Masterclasses – The 3 Secrets to Banish Cravings and Lose Weight on a Plant-Based Diet. See you there!
