GLP-1 receptor agonist medications like semaglutide (sold as Ozempic and Wegovy) are now widely prescribed across the UK for type 2 diabetes and weight management. While these medications can be effective, what you eat alongside them matters enormously — both for managing side effects and for ensuring you get enough nutrition from a reduced food intake.
This page provides general nutritional information only. It is not a substitute for guidance from your prescriber, GP, or dietitian. Always follow the specific dietary advice given to you by your healthcare professional. If you are experiencing severe side effects, contact your prescriber promptly.
GLP-1 medications work by reducing appetite and slowing gastric emptying, which means you naturally eat less. According to NICE guidelines (NG28), people on these medications may consume 500–1,000 fewer calories per day than before starting treatment.
When you eat significantly less food, two things become critical:
This is why tracking what you eat — not just how much — becomes especially important when taking these medications. A calorie counter that also tracks protein and micronutrients can help you make every meal count.
The European Food Safety Authority (EFSA) and UK dietary guidelines recommend at least 0.75g of protein per kilogram of bodyweight per day for the general population. However, when losing weight rapidly, many dietitians suggest aiming higher — around 1.2–1.6g per kg — to help preserve muscle mass. Your prescriber can advise on the right target for you.
| Protein Source | Protein per 100g | Calories per 100g | Notes |
|---|---|---|---|
| Chicken breast (cooked) | 31g | 165 kcal | Lean, versatile, widely available |
| Greek yoghurt (0% fat) | 10g | 57 kcal | Good for breakfast or snacks; gentle on stomach |
| Eggs (boiled) | 13g | 155 kcal | Complete protein; easy to digest |
| Tinned tuna (in water) | 25g | 108 kcal | Convenient; limit to 4 tins per week (NHS advice) |
| Cottage cheese | 11g | 98 kcal | Soft texture; often well tolerated |
| Lentils (cooked) | 9g | 116 kcal | Plant-based; high in fibre too |
| Salmon (cooked) | 25g | 208 kcal | Omega-3 source; slightly higher in fat |
| Tofu (firm) | 8g | 76 kcal | Plant-based; absorbs flavours well |
Side effects like nausea, bloating, and reflux are common in the early weeks. While everyone responds differently, certain food patterns tend to help or hinder. The following is based on commonly reported experiences — your own triggers may differ.
| Food Category | Generally Helpful | Often Problematic | Why |
|---|---|---|---|
| Proteins | Grilled chicken, fish, eggs, cottage cheese | Fried meats, greasy burgers, battered fish | High-fat proteins slow digestion further, worsening nausea |
| Carbohydrates | Brown rice, oats, sweet potato, wholemeal bread | White bread, pastries, sugary cereals | Complex carbs digest more steadily; simple sugars cause spikes |
| Vegetables | Cooked broccoli, spinach, courgette, carrots | Raw onions, cabbage, Brussels sprouts (in large amounts) | Cooked veg is gentler on the stomach; cruciferous veg can cause gas |
| Fruits | Bananas, berries, melon, stewed apple | Citrus on empty stomach, dried fruit | Acidic fruits may worsen reflux; dried fruit is very calorie-dense |
| Dairy | Greek yoghurt, small amounts of cheese | Full-fat cream, large amounts of milk | High-fat dairy can trigger nausea; lactose may cause bloating |
| Drinks | Water, herbal tea, clear broths | Fizzy drinks, alcohol, sugary juices | Carbonation worsens bloating; alcohol adds empty calories |
| Fats | Small amounts of olive oil, avocado, nuts | Deep-fried foods, butter-heavy dishes, cream sauces | Fat slows gastric emptying, which is already slowed by GLP-1s |
Nausea is the most commonly reported side effect of GLP-1 medications, particularly in the first 4–8 weeks as the dose is titrated upwards. The NHS advises speaking to your prescriber if nausea is severe or persistent. From a dietary perspective, these approaches are commonly suggested:
Many people on GLP-1 medications forget to drink enough because their appetite signal is suppressed — and thirst is often mistaken for hunger. Dehydration can worsen nausea, constipation, and fatigue.
The NHS recommends 6–8 glasses of fluid per day as a baseline. If you are losing weight, you may need more. Good options include water, herbal tea, and clear broths. Avoid sugary drinks and limit caffeine if it worsens your symptoms.
When you eat significantly less food, you are at greater risk of not meeting your daily vitamin and mineral needs. The following nutrients are worth paying attention to. Your GP or prescriber can arrange blood tests if you are concerned.
A nutrition tracker that shows vitamin and mineral intake — not just calories — can help you spot gaps before they become deficiencies.
This is an illustrative example only — your prescriber’s guidance takes priority. This sample provides approximately 1,400 calories with a focus on protein and nutrient density.
| Meal | What to Eat | Calories | Protein |
|---|---|---|---|
| Breakfast | Greek yoghurt (150g) with berries (80g) and a tablespoon of seeds | 195 kcal | 16g |
| Mid-morning | 1 boiled egg with 2 oatcakes | 170 kcal | 10g |
| Lunch | Grilled chicken salad with mixed leaves, cucumber, tomato, and a drizzle of olive oil | 350 kcal | 35g |
| Afternoon | Small handful of almonds (20g) and an apple | 175 kcal | 5g |
| Dinner | Baked salmon (120g) with steamed broccoli and a small portion of brown rice (100g cooked) | 430 kcal | 32g |
| Evening | Small bowl of cottage cheese (100g) with cucumber sticks | 110 kcal | 12g |
| Total | 1,430 kcal | 110g |
This sample day prioritises protein at every meal, includes plenty of vegetables, uses complex carbohydrates in modest portions, and keeps fat moderate. The smaller, more frequent meals help manage nausea while keeping energy levels stable.
When you are eating normally, a missed nutrient here or there is unlikely to matter. But when your total food intake is significantly reduced, every meal counts. Tracking helps you:
NutraSafe is designed to give you a complete picture of your nutrition — which is especially valuable when every calorie needs to be nutrient-dense.
Track your protein, vitamins, and minerals — not just calories. See the full picture of your nutrition.
Try NutraSafe FreeFocus on lean protein (chicken, fish, eggs, Greek yoghurt), non-starchy vegetables, complex carbohydrates (wholegrain bread, brown rice, oats), and healthy fats in small amounts. Protein is especially important to preserve muscle mass when eating less. Always follow your prescriber’s specific dietary guidance.
Many people find that very fatty foods, fried foods, high-sugar items, fizzy drinks, and very spicy dishes worsen nausea and other GI side effects. It varies from person to person, so tracking what you eat alongside how you feel can help you identify your personal triggers.
When you eat significantly fewer calories, your body may break down muscle as well as fat for energy. Adequate protein intake (1.2–1.6g per kg of bodyweight per day) helps preserve lean muscle mass. This matters for metabolism, strength, and long-term health outcomes.
When you eat less food overall, you naturally get fewer vitamins and minerals. Common shortfalls include iron, B12, vitamin D, calcium, and zinc. Your prescriber or GP can advise on whether supplements are appropriate for you. Tracking your food intake helps identify specific gaps.
There is no single answer as it depends on your individual circumstances. Most people on GLP-1 medications naturally eat 500–1,000 fewer calories than before. Your prescriber will advise on appropriate calorie targets. The key is ensuring the calories you do eat are nutrient-dense rather than empty.
Last updated: February 2026. Sources: NHS, NICE (NG28), EFSA.