Why eating well matters more on weight loss medicine
Weight loss medicines reduce appetite and can make food less appealing. That means the quality of what you eat matters more, because you may be eating less overall.
The Mounjaro SmPC describes the medicine as an adjunct to a reduced-calorie diet and increased physical activity. Food and activity are part of the treatment, not an optional extra. This guide does not set calorie targets. A dietitian or GP can help you work out an eating pattern that suits your health, preferences and medicines.
Protein: getting enough at each meal
When weight comes off, some of it is lean tissue as well as fat. Eating enough protein, combined with strength exercise, helps protect muscle. Everyday sources include eggs, fish, lean meat, poultry, beans, lentils, tofu, yoghurt and milk.
If your appetite is small, eat your protein food first at each meal. That is often easier than fitting it in at the end, when you may already be full.
Ask your dietitian or GP if you are unsure how much protein you need, especially if you have kidney disease, are older, or have other health conditions.
Fibre, fluids and fruit and vegetables
The NHS Eatwell Guide advises eating at least five portions of a variety of fruit and vegetables a day, and says they should make up just over a third of the food we eat. NHS advice also encourages higher fibre or wholegrain options, such as wholewheat pasta, brown rice, and potatoes with their skins on.
Fibre can help with constipation, which is a common side effect of tirzepatide. Increase fibre gradually and drink enough fluid, because a sudden jump can make bloating worse. If constipation persists, speak to your GP or pharmacist.
The government recommends 6 to 8 cups or glasses of fluid a day, as set out on the NHS Eatwell Guide page. Water is the simplest choice. Sugary drinks add energy without much nutrition, so they are best kept for occasional use.
Sip regularly rather than drinking large amounts in one go, especially if you feel sick. If you are vomiting or have diarrhoea and cannot keep fluids down, contact your GP, out-of-hours service or pharmacist promptly.
Smaller meals and managing nausea
Nausea is very common with tirzepatide. The Mounjaro SmPC lists nausea and diarrhoea as very common, and vomiting and constipation as common. Many people notice these symptoms more during dose increases.
Many people find these approaches help:
- eat smaller meals more often, rather than three large ones
- eat slowly, and stop when you feel comfortably full
- keep very rich, fried or greasy food to a minimum, as it may make nausea worse
- avoid lying down straight after eating
| Symptom | What may help | When to get advice |
|---|---|---|
| Nausea | Smaller, slower meals; less fatty food | If it stops you eating or drinking |
| Constipation | Fibre added gradually, fluids, daily activity | If it lasts or becomes severe |
| Diarrhoea | Fluids; less fatty food for a while | If it continues, or you feel dizzy or unwell |
| Vomiting | Small sips of fluid | If you cannot keep fluids down |
| Severe, persistent abdominal pain | Do not wait it out | Seek urgent medical help, as this may be pancreatitis |
For more on side effects and what to expect, read our guide to weight loss injection side effects.
What a day of eating well can look like
Rules are easier to follow when they become a routine. This is one way to put the advice together, without any calorie figures. Adjust it with your dietitian or GP to suit your health, budget and tastes.
- Breakfast: yoghurt or porridge with fruit, or eggs on wholegrain toast.
- Lunch: beans, lentils, fish or chicken with a large mixed salad or vegetables.
- Snack: a piece of fruit with some nuts or plain yoghurt, in small amounts if you are not hungry.
- Dinner: lean meat, fish or tofu with vegetables and wholewheat pasta, brown rice or potatoes with the skins on.
Between meals, sip water through the day. Keep the portions small if nausea is a problem, and build them up again once your symptoms settle.
Alcohol and weight loss injections
The NHS advises that men and women should not regularly drink more than 14 units a week. If you drink up to that level, spread it over three or more days, and have some alcohol-free days.
Alcohol adds calories without much nutrition, and it can make nausea and stomach upset worse. If you have diabetes or take other medicines, check with your prescriber or pharmacist before you drink.
Strength exercise to protect muscle
The NHS recommends strengthening activities that work all the major muscle groups, including legs, hips, back, abdomen, chest, shoulders and arms, on at least two days a week for adults aged 19 to 64. It also recommends at least 150 minutes of moderate activity a week, or 75 minutes of vigorous activity.
Strength work does not need special equipment. Sit-to-stand from a chair, press-ups against a worktop, resistance bands or light weights all count. If you are new to strength training, ask a qualified instructor or your GP for advice on starting safely.
When to ask for more help
Speak to your GP, prescriber or a dietitian if you are struggling to eat enough, if you feel unwell most days, or if you have concerns about your nutrition. A dietitian can tailor advice to your health conditions and medicines, as explained in our guide to dietitian-led support.
If you are thinking about the longer term, our guide to stopping weight loss injections covers what to plan for.