The UK's most complete GLP-1 guide
Every Question Answered. Every Side Effect Explained.
- How GLP-1 medications work
- Mounjaro vs Wegovy compared
- Injection instructions
- Side effects & solutions
- What to eat on treatment
- FAQs answered
Free tracker included with every download this week
What To Eat On Mounjaro UK
When taking Mounjaro (tirzepatide), your appetite naturally reduces, which changes how you approach food and nutrition. This guide explains which foods work best while on Mounjaro in the UK, how to manage side effects like nausea through diet, and how nutrition strategies compare between Mounjaro and Wegovy. Both medications work alongside a reduced-calorie diet — understanding what to eat helps maximise results and maintain nutrient intake throughout your weight loss journey.
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Enter your height and weight below. Supports both imperial (stone & lbs) and metric (kg). Results include NHS category, healthy weight range, and ethnicity adjustments.
What Is BMI and Why Does It Matter?
Body Mass Index (BMI) is the most widely used screening tool for assessing whether your weight falls within a healthy range. Used by the NHS, GPs, and weight management services across the UK, BMI provides a quick snapshot of your weight relative to your height. The formula is simple: your weight in kilograms divided by your height in metres squared (kg/m²).
While BMI isn't a perfect measure — it doesn't account for muscle mass, bone density, or fat distribution — it remains the standard first step in identifying potential weight-related health risks including type 2 diabetes, cardiovascular disease, high blood pressure, and certain cancers.
The NHS also recommends adjusted thresholds for people of South Asian, Chinese, or Black African heritage — a BMI of 23 or above is classified as overweight, and 27.5 as obese. Our calculator includes this adjustment as a one-click toggle.
Food Choices And Side Effect Management On Mounjaro
On Mounjaro, many people experience reduced appetite and changes in food preferences. Protein-rich foods are especially important because they help preserve muscle mass during weight loss and support satiety — include lean meats, fish, eggs, and Greek yoghurt at each meal. High-fibre foods like vegetables, lentils, and wholegrains help combat constipation, which is common on Mounjaro. Start with smaller portions than usual — your natural fullness signals will guide you.
To manage nausea (very common, especially during dose increases), eat small, frequent meals rather than three large ones. Avoid fatty, greasy, or spicy foods which can worsen nausea. Stay hydrated with water and electrolyte drinks. Some people find that ginger tea, bland carbohydrates like plain rice or toast, and cold foods easier to tolerate. If nausea persists beyond the first few weeks, discuss it with your prescriber — dose adjustment may help. Try our free GLP-1 weight loss calculator to understand how Mounjaro's dual GIP+GLP-1 mechanism may support your individual nutrition goals.
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How It Works
Three simple steps to understand your weight and take action.
Enter your height and weight in our free calculator. Get your BMI, NHS category, healthy weight range, and ethnicity-adjusted thresholds instantly.
If your BMI suggests you're overweight or obese, explore our GLP-1 calculators to project potential weight loss on Mounjaro or Wegovy.
Use our progress tracker to log your weight weekly, visualise your journey with charts, and stay motivated — all stored privately in your browser.
Free Weight Loss Tools & Guides
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Mounjaro Vs Wegovy — Nutrition And Eating Differences
Both Mounjaro and Wegovy work by reducing appetite, but the mechanism differs slightly. Mounjaro is a dual GIP and GLP-1 receptor agonist, whilst Wegovy is GLP-1 only. This dual action in Mounjaro may affect how quickly you feel full and how long satiety lasts — individual experience varies. Clinical trial data showed that Mounjaro users lost an average of 15–21% body weight at the maximum dose, compared to approximately 15% for Wegovy, though results depend on diet and lifestyle alongside medication.
The eating strategy for both is similar: prioritise protein, fibre, and hydration; eat smaller portions; manage side effects through food choice. Your prescriber will assess which medication suits your health profile — neither is universally "better". Use our BMI calculator above to understand your starting point, and our progress tracker to log how your appetite and eating patterns change week to week.
- Dual GIP/GLP-1 receptor agonist
- Up to 22.5% body weight loss (SURMOUNT-1)
- Weekly injection, dose escalation over 20+ weeks
- Available via private prescription in the UK
- Doses: 2.5mg → 5mg → 7.5mg → 10mg → 12.5mg → 15mg
- GLP-1 receptor agonist
- Up to 15–17% body weight loss (STEP trials)
- Weekly injection, 5-step dose escalation
- NHS & private prescription available
- Doses: 0.25mg → 0.5mg → 1mg → 1.7mg → 2.4mg
Mounjaro vs Wegovy: Head-to-Head
A side-by-side comparison of the two most popular GLP-1 weight loss medications available in the UK.
| Feature | Mounjaro | Wegovy |
|---|---|---|
| Drug class | Dual GIP/GLP-1 agonist | GLP-1 agonist |
| Active ingredient | Tirzepatide | Semaglutide |
| Avg. weight loss | 15–22.5% | 12–17% |
| Key trial | SURMOUNT-1 (2022) | STEP 1 (2021) |
| Max dose | 15 mg weekly | 2.4 mg weekly |
| Escalation period | 20–32 weeks | 16–20 weeks |
| Administration | Weekly injection (pen) | Weekly injection (pen) |
| NHS availability | Private prescription only | NHS & private |
| Approx. private cost | £150–£250/month | £150–£300/month |
| Common side effects | Nausea, diarrhoea, constipation | Nausea, vomiting, diarrhoea |
Data sourced from SURMOUNT-1 and STEP 1 clinical trials. Costs are approximate and vary by provider. Always consult a prescriber.
Am I Eligible for Weight Loss Medication?
In the UK, eligibility for GLP-1 weight loss medications like Mounjaro and Wegovy is based on your BMI and overall health profile.
- BMI of 30 or above (obese)
- Age 18 or over
- No contraindicated conditions
- Committed to lifestyle changes
- BMI of 27 or above
- Plus type 2 diabetes
- Or high blood pressure
- Or obstructive sleep apnoea
Use our BMI calculator to check whether your BMI falls within the eligible range.
How We Built These Tools
Every calculator and guide on myweightcheck is built with accuracy and transparency in mind. Our BMI calculator uses the standard WHO formula with NHS-aligned category thresholds. Our GLP-1 projections are modelled on published clinical trial data from SURMOUNT and STEP studies.
All data stays on your device. We don't require sign-ups, and we don't store your health information on any server. Your progress tracker saves data locally in your browser using localStorage, so only you can see it.
We're based in the UK and our tools are designed specifically for UK users — supporting stone & lbs by default, referencing NHS guidelines, using NICE-approved medication data, and linking to GPhC-registered pharmacies.
Frequently Asked Questions
Common questions about BMI, weight loss medications, and our free UK tools.
Can I eat normally on Mounjaro?
No — Mounjaro reduces appetite significantly, so normal portion sizes often feel too large. You'll naturally eat less. This is the medication working as intended. Focus on nutrient-dense foods rather than quantity. Most people adjust within 2–4 weeks.
What foods should I avoid on Mounjaro?
Avoid high-fat, greasy, spicy foods — these worsen nausea. Limit sugar and ultra-processed foods. Alcohol can increase nausea risk. There's no strict "forbidden" list, but these foods are less tolerated. Listen to your body and adjust.
Will I get nutritional deficiencies on Mounjaro?
Eating less food does raise deficiency risk. Prioritise protein, iron-rich foods, B vitamins, and calcium. Consider a multivitamin if concerned. Your GP can advise on blood tests to monitor micronutrients during weight loss.
How does Mounjaro's appetite suppression compare to Wegovy?
Both reduce appetite significantly. Mounjaro's dual mechanism may produce slightly faster satiety in some people, but individual experience varies widely. Your prescriber decides which suits you based on your health profile, not appetite intensity alone.
How long does it take to adjust eating habits on Mounjaro?
Most people adjust within 2–4 weeks as side effects settle. Your taste preferences may shift — some foods suddenly seem unappealing. This usually stabilises by week 8. If eating remains difficult beyond 8 weeks, contact your prescriber to discuss dose adjustment.
Ready to take control of your weight loss journey?
Start with a free BMI check, explore your GLP-1 options, or begin tracking your progress today. No sign-up. No cost. Just results.