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
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Eating On Mounjaro — What You Need To Know
When you start taking Mounjaro (tirzepatide), your relationship with food changes significantly. Many people experience reduced appetite, early fullness, and different food preferences. Understanding how to eat properly on Mounjaro — including which foods work best, appropriate portion sizes, and how to manage nausea — helps you lose weight safely while getting adequate nutrition. This guide covers everything you need to know about eating on this prescription-only GLP-1 and GIP receptor agonist injection.
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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.
How Food And Appetite Change On Mounjaro
Mounjaro works by activating GIP and GLP-1 hormone pathways in your brain and gut, which reduce your appetite and slow how quickly food leaves your stomach. This means you typically feel fuller after smaller meals and may go longer between eating. Most people report that foods they previously enjoyed become less appealing, portion sizes naturally decrease, and hunger signals feel less intense.
In the first few weeks, you may experience nausea, especially after eating fatty or heavily seasoned foods. This usually improves as your body adjusts to the medication. Some people find they develop an aversion to sweet foods or find certain textures (like heavy meats) harder to tolerate. These changes are temporary in many cases, though some appetite suppression persists long-term. The dose titration schedule — starting at 2.5mg and increasing every 4 weeks up to 15mg — means your appetite adjustments happen gradually, giving your eating habits time to adapt alongside your body's changing signals.
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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
Everything you need to understand your weight, explore medication options, and track your progress — completely free.
Best Foods And Eating Strategies On Mounjaro
Focus on protein-rich, nutrient-dense foods in smaller portions: lean poultry, fish, eggs, Greek yoghurt, and pulses are well-tolerated and help prevent muscle loss during weight loss. Eat slowly and mindfully — nausea is often worse if you eat too quickly. Avoid fatty, greasy, or heavily spiced foods in the first weeks; gradually reintroduce them as tolerance improves. Stay hydrated with water throughout the day. Keep easy, low-calorie options available: vegetable soups, cottage cheese, and light salads. If nausea is severe, try eating smaller, more frequent meals rather than three large ones. Your GP or a dietitian can provide personalised nutrition guidance tailored to your Mounjaro dose and health needs.
- 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.
What should I eat when starting Mounjaro to avoid nausea?
Start with bland, easily digestible foods: plain chicken, white rice, toast, bananas, and applesauce. Avoid fried, fatty, and spicy foods initially. Eat slowly in small portions and stay hydrated. Most nausea improves within 1–2 weeks as your body adjusts. If severe nausea persists, contact your prescriber.
Can I eat normal meals on Mounjaro, or must I diet strictly?
You don't need extreme restriction — Mounjaro naturally reduces how much you eat by making you feel fuller sooner. Most people find they eat 30–50% less without conscious dieting. However, quality matters: prioritise protein, vegetables, and whole grains over ultra-processed foods to maintain nutrition and muscle mass during weight loss.
Will I lose muscle on Mounjaro if I eat less?
Eating adequate protein (aim for 1.2–1.6g per kg of body weight daily) and doing resistance exercise 2–3 times weekly helps preserve muscle during weight loss. Even on Mounjaro with reduced appetite, conscious protein choices — like Greek yoghurt, fish, and lean meat — support muscle retention alongside your weight loss journey.
Is it normal to feel sick after eating on Mounjaro?
Mild nausea after eating is very common, especially in the first 4 weeks and when increasing your dose. It usually improves as your body adjusts. Eating slowly, choosing bland foods, and avoiding large meals helps. If nausea is severe or persistent beyond 2 weeks, contact your prescriber — dose adjustment may help.
Can I use our GLP-1 weight loss calculator to plan meals on Mounjaro?
Our free GLP-1 weight loss calculator helps you understand projected weight loss at your current dose, which can inform realistic nutrition goals. Alongside the BMI calculator, it gives context for how much weight you might lose, helping you plan sustainable eating changes that support your overall health progress.
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.