What to Eat on GLP-1 Medication

There is no single official diet on Mounjaro, Wegovy or other GLP-1 medicines, but the principles are well established. Because these medicines reduce appetite and slow stomach emptying, the aim is to eat smaller, balanced meals that put protein first, include plenty of fibre from vegetables, fruit and wholegrains, and keep you well hydrated, while limiting greasy, very sugary and alcoholic foods and drinks that often worsen side effects. Getting enough nutrition matters as much as eating less. This guide explains what to eat, how to manage side effects through food, and when to get professional advice.

How GLP-1 medicines change eating

Understanding how these medicines affect your body helps explain the dietary advice.

• Reduced appetite. GLP-1 medicines act on areas of the brain involved in hunger and fullness. Many people describe less "food noise".
• Feeling full sooner. You may feel satisfied after much smaller portions than before.
• Slower stomach emptying. Food stays in the stomach longer, particularly early in treatment and after dose increases. This contributes to fullness but also to nausea, reflux and bloating.
• Changes in food preferences. Some people find rich, fatty or sweet foods less appealing, or that they cause discomfort.

Because you're likely to eat less, every meal matters more for nutrition. The aim shifts from simply eating less to eating well in smaller amounts.

The foundations: a balanced plate

The NHS Eatwell Guide provides a sensible foundation for most adults, with adjustments for smaller portions and a focus on protein.

A practical approach is to fill around a quarter to a third of your plate with protein, around half with vegetables or salad, and the rest with wholegrain or starchy foods, adjusting portions to your appetite.

Protein: why it matters most

Protecting muscle

When you lose weight, some of what you lose is lean mass, which includes muscle. Body composition studies within the STEP 1 (semaglutide) and SURMOUNT-1 (tirzepatide) trials found that most weight lost was fat, but lean mass made up a meaningful minority. Muscle supports strength, mobility, balance and metabolic health, especially as you get older.

Eating enough protein, combined with resistance exercise, is the main way to help preserve muscle during weight loss. See our guides to protein on GLP-1 medication and preserving muscle.

How much?

UK reference intakes for protein in adults are around 0.75 g per kilogram of body weight per day. Many weight management specialists suggest aiming higher during active weight loss on GLP-1 medicines, but there is no single agreed figure, and needs vary with age, activity, kidney function and other conditions. Ask your prescriber, GP or a dietitian for a personal target, especially if you have kidney disease.

Practical tips

• Eat protein first at each meal, so you get it before you feel full.
• Spread protein across the day, including breakfast.
• Choose protein-rich snacks, such as Greek yoghurt, cottage cheese, a boiled egg, edamame or a small handful of nuts.
• If appetite is very low, soups, smoothies made with milk or yoghurt, or milk-based drinks can be easier to manage.
• Protein shakes can help some people but aren't essential; whole foods also provide other nutrients.

Fibre and constipation

Constipation is one of the most common side effects of GLP-1 medicines. Eating less overall can reduce fibre and fluid intake, making it worse.

UK guidance recommends that adults aim for 30 g of fibre a day. Most people in the UK eat less than this. Good sources include:

• Oats, wholegrain bread, wholewheat pasta and brown rice
• Beans, lentils and chickpeas
• Vegetables, especially with skins
• Fruit, including berries, pears, apples and kiwi
• Nuts and seeds, such as chia and ground flaxseed

Increase fibre gradually, as a sudden increase can cause bloating, and drink plenty of fluids alongside it. If constipation persists, a pharmacist can advise on suitable remedies. See our guide to constipation on GLP-1 medication.

Hydration

Eating less means getting less fluid from food, and side effects such as vomiting or diarrhoea increase fluid losses. Dehydration can cause dizziness, headaches and constipation, and in severe cases can affect the kidneys.

The NHS Eatwell Guide suggests 6 to 8 cups or glasses of fluid a day for most adults, more in hot weather or with exercise. Water, milk, sugar-free drinks, tea and coffee all count. Sipping fluids through the day is often easier than drinking large amounts at once, and some people find drinking between rather than with meals reduces fullness and nausea. See our guide to hydration on GLP-1 medication.

Eating to reduce side effects

Many common side effects can be eased by adjusting how and what you eat. The SmPCs and NHS guidance for these medicines suggest similar practical steps.

For more detail, see our guides to nausea, reflux, burping and indigestion and foods that worsen GLP-1 side effects.

Foods and drinks to limit

No food is strictly off-limits, but many people find it helps to limit:

• Greasy and fried foods, which stay in the stomach longer and often worsen nausea and reflux
• Very rich, creamy or heavy meals
• Large portions, especially in one sitting
• Very sugary foods and drinks, which provide calories with few nutrients and can cause discomfort
• Fizzy drinks, which can worsen bloating and burping
• Alcohol, which adds calories, may worsen side effects, and is linked to pancreatitis
• Ultra-processed snacks, which are easy to overeat and often low in protein and fibre

Alcohol

UK Chief Medical Officers' guidelines advise drinking no more than 14 units a week on a regular basis, spread over three or more days, with several drink-free days. Many people on GLP-1 medicines report a reduced desire for alcohol. If you have diabetes and take insulin or a sulfonylurea, alcohol increases the risk of low blood sugar. See our guide to Mounjaro and alcohol.

Meal patterns and portion sizes

Smaller, regular meals

Three small meals and one or two protein-rich snacks suits many people. Others prefer three meals with no snacks. The important points are:

• Don't skip meals entirely just because you're not hungry, as this can make it harder to meet your nutritional needs and may lead to dizziness or fatigue.
• Stop eating as soon as you feel comfortably full. Overeating on these medicines often causes nausea or vomiting.
• Eat slowly, putting your cutlery down between mouthfuls.

Portion guide

Smaller plates and bowls can help. A rough guide for a main meal might be a palm-sized portion of protein, two handfuls of vegetables, and a fist-sized portion of wholegrains or potatoes, adjusted to your appetite.

A sample day

This is an illustration, not a prescription. Your needs may differ.

For more ideas, see our GLP-1 meal plan guide.

Eating too little

GLP-1 medicines can suppress appetite so much that some people eat too little. Signs include:

• Feeling weak, dizzy or faint
• Persistent tiredness
• Hair thinning (which can also occur with rapid weight loss)
• Difficulty concentrating
• Feeling cold
• Very rapid weight loss

If you notice these, speak to your prescriber. They may suggest adjusting your dose, or a referral to a dietitian. Our guide to hair loss on Mounjaro has more information.

Vitamins and minerals

Eating less food overall can make it harder to get enough of some vitamins and minerals. Nutrients to keep an eye on include:

• Calcium and vitamin D, for bone health. UK guidance recommends that everyone considers a daily 10 microgram vitamin D supplement during autumn and winter.
• Iron, particularly for women who menstruate.
• Vitamin B12, especially for people following a vegan diet or taking metformin.
• Folate, particularly for anyone who could become pregnant.

A varied diet is the first priority. A general multivitamin may be reasonable for some people, but it isn't a substitute for good food. Ask your pharmacist or GP before starting supplements, especially if you take other medicines. See our guide to vitamins and supplements on GLP-1 medication.

Special situations

Type 2 diabetes

If you have diabetes and take insulin or a sulfonylurea, eating much less while on a GLP-1 medicine increases the risk of hypoglycaemia (low blood sugar). Your diabetes team may need to adjust your medicines. Don't change them yourself. See our guide to GLP-1 medicines and type 2 diabetes.

Kidney disease

People with kidney disease may need to limit protein and some minerals, and are more vulnerable to dehydration. Seek individual advice from your kidney team or a dietitian.

Vegetarian and vegan diets

Plant-based diets can meet protein needs with planning. Good sources include tofu, tempeh, lentils, beans, chickpeas, edamame, soya milk and yoghurt, and seitan. Pay attention to vitamin B12, iron, calcium, iodine and omega-3 fats.

Older adults

Older adults are more at risk of losing muscle and becoming frail. Protein, strength exercise and enough calories are particularly important. See our guide to GLP-1 medicines over 65.

Oral semaglutide

If you take Wegovy tablets (oral semaglutide), follow the specific instructions in the patient leaflet. These require the tablet to be taken on an empty stomach with a small sip of water, followed by a waiting period before eating, drinking or taking other oral medicines. Orforglipron (Foundayo) doesn't have the same food and water restrictions, according to the MHRA. See our guide to oral semaglutide.

Building habits for the long term

The eating habits you build on GLP-1 medication can help support long-term weight maintenance, including if you later reduce or stop treatment. Trials show that weight is often regained after stopping, so habits are helpful but rarely enough on their own for most people. See our guide to weight regain after stopping GLP-1 medication.

Habits worth building include regular meals, protein at each meal, plenty of fibre, limiting alcohol and liquid calories, and noticing hunger and fullness cues.

Getting professional support

A registered dietitian can provide personalised advice, particularly if you have other health conditions. NHS specialist weight management services include dietetic support, and some private providers offer access to dietitians or nutritionists. You can compare what different regulated services include on our providers page and see how service costs compare on our prices page.

For more on nutrition, explore our diet topic hub and the wider guides library.

Practical tips for everyday life

Planning and shopping

• Keep protein-rich staples to hand: eggs, Greek yoghurt, tinned fish, frozen chicken or fish, tofu, tinned beans and lentils.
• Frozen vegetables and fruit are nutritious, affordable and reduce waste when appetite is small.
• Batch-cook small portions and freeze them, so a balanced meal is easy when you don't feel like cooking.
• Read food labels for protein, fibre, sugar and fat content; the UK traffic-light labels can help.

Eating out and social occasions

• Choose smaller portions, starters as mains, or share dishes.
• Prioritise the protein and vegetables on your plate.
• Don't feel obliged to finish everything. Stopping when full helps avoid nausea.
• Be cautious with alcohol, rich sauces and fried foods.
• If you're asked about your eating, you don't have to explain your medical treatment.

Working days and shifts

• Pack small, protein-rich snacks for long days.
• Keep a water bottle at hand to sip through the day.
• If you work shifts, aim for regular eating times relative to your sleep, rather than skipping meals entirely.

Myths about eating on GLP-1 medication

"You can eat anything because the medicine does the work"

GLP-1 medicines reduce appetite, but food quality still matters for nutrition, muscle, side effects and long-term health. Eating mainly ultra-processed, low-protein foods can leave you short of key nutrients.

"You should eat as little as possible to maximise weight loss"

Eating too little increases the risk of muscle loss, fatigue, nutritional deficiencies and gallstones. The aim is a sustainable, balanced intake, not the lowest possible.

"Carbohydrates must be cut out"

There is no need to cut out carbohydrates entirely. Wholegrains, fruit, vegetables and pulses provide fibre and nutrients that help with constipation and overall health. Choosing higher-fibre options and sensible portions is usually enough.

"Protein shakes are essential"

They can be convenient, but they aren't essential. Many people meet their protein needs from ordinary foods.

"Special supplements boost GLP-1 effects"

Some products are marketed as natural alternatives or boosters for GLP-1 medicines. There is no good evidence that these replicate or enhance the effects of licensed medicines, and some may interact with other treatments. Speak to your pharmacist before taking any supplement.

When to speak to a professional

Speak to your prescriber, GP, pharmacist or a dietitian if:

• You're struggling to eat enough, or are skipping meals regularly
• You're losing weight very quickly, or feel weak, dizzy or faint
• Side effects such as nausea, constipation or reflux are affecting your daily life
• You have diabetes and are having low blood sugar episodes
• You have kidney disease or another condition that affects your diet
• You have a history of an eating disorder, or are worried about your relationship with food
• You're pregnant, planning pregnancy or breastfeeding

Seek urgent medical help (NHS 111, or 999 in an emergency) if you have:

• Severe, persistent abdominal pain that may spread to your back, with or without vomiting (a possible sign of pancreatitis)
• Pain in the upper right abdomen, especially after eating, with fever or yellowing of the skin or eyes (possible gallbladder problems)
• Vomiting that won't stop, or inability to keep fluids down
• Signs of dehydration, such as dizziness, confusion, very dark urine or passing little urine
• Symptoms of very low blood sugar, such as confusion, sweating, shaking or drowsiness