What to eat during GLP-1 treatment

Why does appetite change?

Semaglutide and tirzepatide activate GLP-1 receptors in the brain that reduce hunger and increase satiety. They also slow gastric emptying: food stays longer, so you feel full sooner and for longer. A clinical study showed that semaglutide reduced spontaneous calorie intake by about 24% and decreased preference for high-fat foods.

The first days: gentle foods

While your body adjusts, these foods tend to sit well:

• Toast, crackers, white rice, oatmeal.
• Light soups and broths.
• Banana, applesauce.
• Plain Greek yoghurt.
• Scrambled or boiled eggs.
• Steamed or roasted vegetables (courgette, carrots).

If your appetite is very low, try protein + fibre snacks: yoghurt with fruit, a handful of nuts, hummus with carrot sticks.

Plate structure

A simple guide for each meal:

• 50% vegetables (salad, cooked veg, fruit).
• 25% protein (fish, chicken, egg, tofu, legumes).
• 25% complex carbs (sweet potato, brown rice, quinoa, whole-grain bread).

Always start with the protein. These medications bring fullness quickly, and protein is what you need most to preserve muscle mass during weight loss.

Foods to limit

• Fried and very fatty food (chips, battered food, pastries): fats already digest slowly; combined with slower gastric emptying, they can cause nausea, reflux and bloating.
• Sugary drinks and refined sweets (fizzy drinks, juice, sweets): cause blood sugar spikes and digestive stress.
• Carbonated drinks, alcohol and very spicy food: can worsen gastrointestinal side effects.

Hydration

Aim for 1.5 to 2.5 litres (50–85 oz) of water a day. When you feel less hungry, you also tend to drink less without realising. Good hydration helps prevent constipation (a common side effect) and is essential for metabolism. Drink between meals, not during: this avoids filling up before eating what you need.

Small, frequent meals

Eating smaller portions every 3–4 hours works better than 2–3 large meals. Large meals increase the risk of nausea and vomiting. Eat slowly and stop at the first sign of fullness — the "full" signal takes about 20–30 minutes to reach the brain.

Nutritional deficiencies: what to watch

When eating less, you may not cover all your needs. According to recent studies in GLP-1 users:

• Vitamin D deficiency in 13.6% after 12 months of treatment.
• Insufficient intake of potassium, magnesium and iron in over 85% of patients studied.
• Up to 2.6% showed B-vitamin deficiencies.

A daily multivitamin with iron, zinc, B12 and folic acid is a reasonable measure. If you notice fatigue, weakness or hair loss, mention it to your doctor — they can order a micronutrient blood test.

Protein and muscle mass

Roughly 20–30% of weight lost by any method (diet, surgery or medication) is lean mass. To minimise this:

• Daily protein: 0.8 to 1.6 g per kg of body weight, tailored by your healthcare provider.
• Resistance exercise: two to three weekly strength sessions (weights, bands, bodyweight) help preserve muscle.

More on this topic in our guide 8 GLP-1 myths (myth 7: "GLP-1s destroy muscle").

Easing nausea with food

• Choose bland, low-fat foods: toast, rice, broth, banana.
• Cold food is often better tolerated (less smell).
• Steamed or roasted vegetables instead of raw.
• Ginger or peppermint tea (unsweetened).
• Stay seated or standing for at least 30 minutes after eating.

More detail in our guide on nausea and when to call your doctor.

Related guides

• Nausea: what's normal and when to consult — why it happens, how long it lasts and warning signs.
• How to use your GLP-1 pen correctly — injection, sites, storage and missed doses.
• 8 GLP-1 myths — what the science says about muscle, weight, thyroid and more.

Sources: Cleveland Clinic (GLP-1 Diet); Cambridge University Hospitals NHS (Dietary advice for tirzepatide); Harvard Health (Nutrient deficiencies and GLP-1); Frontiers in Nutrition (2025); Nature – International Journal of Obesity (2025); Obesity Medicine Association (2025); Blundell et al., Diabetes Obes Metab 2017.