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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What To Eat And Drink On Mounjaro
When you start taking Mounjaro, your appetite naturally decreases, but knowing what to eat and drink can help you feel your best whilst managing the medication's common side effects like nausea and changes in digestion. This guide covers practical dietary strategies for UK adults using tirzepatide, based on clinical experience and NHS nutritional guidance. Always discuss dietary changes with your GP or prescriber, especially if you have existing health conditions.
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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.
Foods And Drinks To Prioritise On Mounjaro
When taking Mounjaro, smaller portions of nutrient-dense foods work best. Focus on protein-rich foods like lean chicken, fish, eggs, Greek yoghurt, and legumes — these help maintain muscle mass during weight loss and keep you fuller longer. Stay well-hydrated by drinking water throughout the day; nausea is common on Mounjaro, and sipping water regularly helps manage this side effect. Include plenty of non-starchy vegetables (broccoli, spinach, peppers, courgettes) which are low-calorie and high in fibre. Eat slowly and chew thoroughly — this supports digestion and reduces stomach discomfort. Avoid or limit sugary drinks, caffeine on an empty stomach, and very fatty foods, which can trigger nausea. Many people find that eating smaller meals every 3–4 hours, rather than three large meals, works better with Mounjaro's appetite-suppressing effect. Your GLP-1 weight loss calculator can help you project realistic outcomes as you adjust your eating patterns.
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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.
Foods And Drinks To Avoid Or Limit
High-fat and fried foods often cause nausea and stomach discomfort on Mounjaro — limit takeaways and heavily processed foods. Sugary foods and drinks (sweets, fizzy drinks, desserts) can trigger nausea and work against your weight loss goals. Very hot foods or drinks may worsen reflux or nausea; let food cool slightly before eating. Alcohol, especially on an empty stomach, can intensify nausea and dizziness — if you do drink, do so with food and in moderation. Carbonated drinks can cause bloating and stomach discomfort. Large meals are difficult to manage on Mounjaro; your reduced appetite means you'll naturally eat less, so eating too much at once often triggers nausea and vomiting. Consider using our progress tracker to log what you eat and how you feel — this helps you identify which foods work best for your body whilst on tirzepatide.
- 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?
Your appetite will naturally decrease significantly on Mounjaro. Most people find they can only manage smaller portions — often 25–50% of their usual meal size. This is expected and part of how the medication works. Eat when you feel hungry, stop when you feel satisfied, and don't force yourself to finish meals. Your prescriber can advise if your appetite changes seem unusual.
What should I do if I feel nauseous when eating on Mounjaro?
Nausea is a common side effect, especially in the first few weeks. Eat smaller, more frequent meals; avoid fatty or greasy foods; stay hydrated with water; eat slowly; and try ginger tea or sucking ginger sweets. If nausea is severe or persistent beyond a few weeks, contact your GP or prescriber — dose adjustment may help.
Do I need to follow a specific diet whilst on Mounjaro?
No specific diet is required, but a balanced approach works best. Focus on lean protein, vegetables, whole grains, and healthy fats. Mounjaro works alongside lifestyle changes — your reduced appetite makes a calorie deficit easier to maintain. Many people benefit from speaking with a dietitian, especially if they have type 2 diabetes or other health conditions.
Is it safe to drink alcohol on Mounjaro?
Alcohol is safe in moderation but may increase nausea, dizziness, or low blood sugar risk, especially if you're also taking diabetes medication. Always eat food with alcohol, keep intake moderate, and monitor how you feel. Discuss alcohol use with your GP or prescriber if you have concerns.
How does Mounjaro compare to Wegovy when it comes to diet?
Both Mounjaro (tirzepatide) and Wegovy (semaglutide) reduce appetite significantly, so dietary approaches are similar — smaller portions, protein-focused, limited high-fat foods. Mounjaro uses a dual GIP and GLP-1 mechanism whilst Wegovy is GLP-1 only, but both work best with a balanced diet and lifestyle changes. Your prescriber can advise which suits you best.
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.