A Nutritionist’s Take on Foods to Eat and Avoid on Ozempic & Other GLP-1 Medications.

Why Nutrient Density Matters on GLP-1 Medications

GLP-1 medications such as Ozempic and Mounjaro have changed the landscape of weight management. These drugs enhance satiety signalling in the brain and slow gastric emptying which reduces appetite and help people achieve a clinically meaningful weight loss¹. For some, this quietening of appetite which is often described as reducing “food noise”, feels liberating. But while appetite drops quickly, the body’s requirement for protein, fibre, vitamins and minerals does not and when food intake reduces significantly, nutrition needs to become more intentional. So lets dive into the foods to eat and avoid on Ozempic & other GLP-1 medications. 

Do you need a special diet on GLP-1?

There is no official “GLP-1 diet.” These medications are not paired with a specific branded eating plan, but fundamentally they alter how much you eat and how quickly you feel full. That alone changes the nutritional equation.

When intake falls, the margin for error narrows and with smaller portions, there are simply fewer opportunities across the day to meet essential nutrient requirements. Without planning, this can lead to what I often describe as quiet under-nutrition that presents itself as insufficient protein, low fibre, inadequate calcium, iron or B vitamins, and a gradual decline in dietary quality.

Emerging research supports this concern. A 2025 paper in Frontiers in Nutrition analysing three-day food records from individuals using GLP-1 receptor agonists found intakes of fibre, calcium, magnesium, potassium, iron and several vitamins frequently fell below recommended levels². Fibre intake averaged around 14g per day which is less than half the UK recommendation of 30g.

Eating less does not mean you need less nutrition. It means each bite needs to work harder.

Protein: the non-negotiable nutrient

Of all the nutrients, protein deserves particular attention. Muscle is not just about strength or appearance, it’s metabolically active tissue that supports glucose regulation, immune function and long-term metabolic health. It also acts as a reservoir of amino acids during periods of physiological stress.

Data from large weight loss trials show that most weight lost is fat mass, with around one-quarter typically coming from lean tissue³. The proportion of lean mass lost is similar to what we see with diet-induced weight loss and can be influenced by protein intake, resistance training and the total amount of weight lost. Lean mass does include more than just skeletal muscle, but preserving muscle is essential, particularly in midlife and older adults, where age-related muscle loss (sarcopenia) is already occurring.

The UK reference intake for protein (0.8g per kilogram of body weight) is designed to prevent deficiency in weight-stable adults. During weight loss, especially when appetite is suppressed, higher intakes are advisable and evidence suggests a range of 1.2–1.6g per kilogram of body weight per day supports lean mass retention during energy restriction⁴. For a 70kg adult, that equates to roughly 84–112g per day and if you have a BMI over 30 then you should take 75% of your bodyweight to calculate this equation.

For many people on GLP-1 medication, reaching this target requires intention. Protein should ideally be distributed across the day in smaller eating occasions rather than concentrated in a single meal, as muscle protein synthesis responds best to regular stimulation.

Practical protein anchors include:

• Eggs
• Poultry
• Fish (particularly oily fish)
• Greek yoghurt or skyr
• Tofu and edamame
• Lentils and beans
• Fortified dairy or soya alternatives

If your appetite is very low, protein powders or clear protein drinks can be pragmatic tools. While not a substitute for whole foods long term, they can help bridge gaps during periods when eating feels difficult.

After this blog, check out a Dietitian’s guide on hitting your protein intake when appetite is low.

Nutrient density: making every bite count

Nutrient density refers to the concentration of beneficial nutrients relative to energy content, so, rather than focusing on volume, the goal shifts to maximising:

• Protein
• Fibre
• Unsaturated fats
• Vitamins and minerals

Compact, high-value foods become really useful. Eggs provide complete protein and vitamin B12. Tinned sardines offer omega-3 fats and calcium in a small portion. Dark leafy greens deliver folate and magnesium with minimal energy load. Seeds add fibre and healthy fats in just one tablespoon.

This approach is not about restriction or perfection. It is about optimisation.

A nutrient watchlist on glp-1

When appetite is low, these nutrients deserve particular attention:

• Protein – to preserve lean mass
• Fibre – to support bowel function and cardiometabolic health
• Calcium + vitamin D – to protect bone density
• Iron, B12 and folate – to support energy and red blood cell production
• Magnesium and potassium – often low when total intake falls [2]

Fibre and gut health: quality and tolerance matter

Fibre intake often drops significantly when food intake reduces. Yet fibre plays a central role in digestive health, cholesterol regulation and blood sugar stability which are all very relevant to someone who is very overweight or obese. A large meta-analysis in The Lancet showed that higher fibre intake is associated with reduced cardiovascular disease and all-cause mortality risk⁵.

The UK recommendation is 30g per day, but most adults already fall short. GLP-1 medications can compound this through smaller portion sizes and reduced dietary diversity. However, fibre is not one-size-fits-all, particularly when gastric emptying is slowed.

There are broadly two types of fibre:

Soluble fibre, which dissolves in water and forms a gel-like substance in the gut. This type is generally better tolerated on GLP-1 medications and may feel gentler on digestion. It is found in:

• Oats (beta-glucan)
• Beans and lentils
• Apples and pears
• Chia seeds
• Ground flaxseed
• Psyllium

Soluble fibre can help regulate blood glucose and cholesterol and may be less likely to cause bloating when introduced gradually.

Insoluble fibre, found in wholegrains, wheat bran and some vegetables, adds bulk to stool and speeds transit time. While important, large increases in insoluble fibre too quickly can worsen bloating or discomfort in some people using GLP-1 medications.

The key is gradual layering, sometimes described as “fibre stacking.” Small amounts across the day are better tolerated than one large high-fibre meal. For example:

• Oats topped with seeds
• A spoonful of lentils stirred into soup
• Berries with yoghurt
• Edamame as a snack

Hydration is also essential alongside fibre. Adequate fluid intake supports bowel regularity and reduces constipation risk.

Foods That Work Well on GLP-1

While no foods are strictly off-limits, certain types tend to be both better tolerated and nutritionally advantageous.

Soft-textured, protein-rich foods are often easier to manage when appetite is low:

• Scrambled eggs
• Greek yoghurt
• Cottage cheese
• Flaked salmon
• Tofu

Small portions of wholegrains and legumes can support fibre intake without overwhelming the stomach and healthy fats such as olive oil, avocado and nuts add energy density without large volume, which can be useful when overall intake is modest.

Foods that may worsen side effects

GLP-1 medications slow gastric emptying¹. Large, high-fat meals may remain in the stomach longer and worsen nausea or reflux, so, fried foods and very rich dishes are therefore commonly less well tolerated.

Alcohol can aggravate nausea and disrupt appetite regulation.

Highly refined, low-protein foods are not inherently “forbidden,” but when appetite is limited, they displace more nutrient-dense options and offer little satiety or nutritional value. This is not about banning foods, it’s about tolerability and nutritional opportunity.

Managing Common Nutrition-Related Side Effects

Nausea:
Smaller, more frequent meals. Cold foods. Avoiding very fatty or strongly flavoured dishes initially.

Early fullness:
Prioritise protein first. Avoid large volumes of fluid with meals.

Constipation:
Gradual fibre increase. Adequate hydration. Light physical activity.

Fatigue:
Assess overall intake. Ensure sufficient protein and iron-rich foods. In the UK, vitamin D supplementation (10 micrograms daily) is recommended during autumn and winter for most adults [7].

Bone Health: An Overlooked Consideration

Reduced intake can affect calcium and vitamin D status. Bones require consistent nutrient supply alongside mechanical loading from resistance exercise. Dairy, fortified plant milks, tofu and small fish with bones are practical additions. Weight loss without resistance training increases the risk of lean tissue and bone density decline and even light strength training twice weekly can make a meaningful difference.

The bigger picture

GLP-1 medications can significantly improve glycaemic control and reduce cardiovascular risk factors. But medication alone does not guarantee optimal nutrition.

Successful long-term outcomes depend on:

• Preserving muscle
• Supporting bone health
• Maintaining dietary diversity
• Protecting micronutrient status
• Developing sustainable eating patterns

If you are regularly struggling to eat, losing strength quickly, or your intake is persistently very low, it is sensible to speak with your prescriber and consider dietetic support. Eating well on GLP-1 medication is not about forcing food or following rigid rules, it’s about intentional, nutrient-focused choices that support your physiology while appetite is lower.

Weight loss is one marker of progress but strength, energy, resilience and metabolic health matter just as much.

When appetite shrinks, your nutritional margin for error shrinks with it and that is why nutrient density matters.

References

1. Liu Q. K. (2024). Mechanisms of action and therapeutic applications of GLP-1 and dual GIP/GLP-1 receptor agonists. Frontiers in endocrinology, 15, 1431292. https://doi.org/10.3389/fendo.2024.1431292
2. Johnson, B., Milstead, M., Thomas, O., McGlasson, T., Green, L., Kreider, R., & Jones, R. (2025). Investigating nutrient intake during use of glucagon-like peptide-1 receptor agonist: a cross-sectional study. Frontiers in nutrition, 12, 1566498. https://doi.org/10.3389/fnut.2025.1566498
3. Look, M., Dunn, J. P., Kushner, R. F., Cao, D., Harris, C., Gibble, T. H., Stefanski, A., & Griffin, R. (2025). Body composition changes during weight reduction with tirzepatide in the SURMOUNT-1 study of adults with obesity or overweight. Diabetes, obesity & metabolism, 27(5), 2720–2729. https://doi.org/10.1111/dom.16275
4. Leidy, H. J., Clifton, P. M., Astrup, A., Wycherley, T. P., Westerterp-Plantenga, M. S., Luscombe-Marsh, N. D., Woods, S. C., & Mattes, R. D. (2015). The role of protein in weight loss and maintenance. The American journal of clinical nutrition, 101(6), 1320S–1329S. https://doi.org/10.3945/ajcn.114.084038
5. Reynolds, A., Mann, J., Cummings, J., Winter, N., Mete, E., & Te Morenga, L. (2019). Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. Lancet (London, England), 393(10170), 434–445. https://doi.org/10.1016/S0140-6736(18)31809-9
6. NHS. Vitamin D Supplementation Guidance for Adults. 2023. – (https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-d/)