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 Food Should You Eat on Mounjaro?
When taking Mounjaro (tirzepatide), food choices matter as much as the medication itself. Mounjaro works by reducing appetite and helping you feel fuller faster, so the right nutrition supports these effects and helps you lose weight sustainably. This guide covers what to eat on Mounjaro, how to manage appetite changes, and practical nutrition strategies whilst on treatment in the UK. Always consult your GP or prescriber for personalised dietary advice alongside your Mounjaro prescription.
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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.
Nutrition Strategy While on Mounjaro
Mounjaro (tirzepatide) changes how your body responds to food, so a structured approach to nutrition works best. Focus on protein-rich foods — lean chicken, fish, eggs, Greek yoghurt, and legumes — as these help preserve muscle mass during weight loss and keep you satisfied longer. Include plenty of non-starchy vegetables like broccoli, spinach, peppers, and courgettes to add volume and nutrients without excess calories.
- Eat slowly and chew thoroughly — Mounjaro slows gastric emptying, so small, frequent meals work better than large portions
- Stay hydrated — drink water throughout the day, as nausea is common and dehydration worsens it
- Choose whole grains in moderation — brown rice, oats, and wholemeal bread are better than refined carbohydrates
- Limit high-fat, fried, and greasy foods — these can trigger nausea and stomach discomfort whilst on Mounjaro
- Avoid sugary drinks and processed snacks — they provide calories without satiety
Track your intake using our GLP-1 weight loss calculator to monitor progress and adjust portions as your appetite naturally decreases. Your prescriber or a registered dietitian can provide personalised meal plans based on your health needs.
Clinically BackedWeight Loss
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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 to Avoid and Managing Side Effects
Some foods are more likely to cause discomfort on Mounjaro. Avoid or minimise: very fatty meals (increase nausea risk), high-sugar foods (cause energy crashes), large portions (trigger bloating), and spicy foods (may irritate the stomach). Dairy intolerance is common — if you experience bloating or stomach pain after milk products, try alternatives like oat or almond milk.
- Ginger tea and crackers can help manage mild nausea naturally
- Eat smaller portions more frequently rather than three large meals
- Wait at least 30 minutes after injecting Mounjaro before eating, if nausea occurs
- Keep a food diary to identify personal triggers — everyone responds differently
Use our BMI calculator and weight converter to track how your nutrition and Mounjaro work together over time. If nausea, vomiting, or stomach pain persists, contact your GP — these may be signs your dose needs adjusting.
- 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 whilst taking Mounjaro?
Not initially — Mounjaro reduces appetite significantly, so you'll likely eat less and feel full faster. This is intentional and helps weight loss. Over time, some appetite returns, but most people continue eating smaller portions than before. Your prescriber can advise if appetite suppressant effects are too strong.
What should I eat on days I feel very nauseous on Mounjaro?
Stick to bland, easy-to-digest foods: plain toast, crackers, rice, bananas, boiled potatoes, and clear broths. Avoid fatty, spicy, and strongly flavoured foods. Stay hydrated with water or electrolyte drinks. Nausea usually improves within a few days of starting or increasing your dose, but contact your GP if it persists beyond a week.
Is calorie counting necessary on Mounjaro?
Whilst Mounjaro reduces hunger, you'll still lose weight faster with a gentle calorie deficit. You don't need strict counting — focus on portion sizes, protein intake, and whole foods. Many people naturally eat fewer calories because the medication suppresses appetite. Your prescriber or dietitian can advise on your specific calorie needs.
Can I drink alcohol whilst on Mounjaro?
Alcohol should be limited. It can trigger nausea, worsen stomach discomfort, and affect blood sugar control. If you do drink, choose lower-sugar options like dry wine or spirits with sugar-free mixers, and always eat food beforehand. Never drink on an empty stomach whilst on Mounjaro.
How does Mounjaro differ from Wegovy when it comes to diet?
Both Mounjaro (tirzepatide) and Wegovy (semaglutide) reduce appetite similarly, so dietary principles are nearly identical. Mounjaro is a dual GIP and GLP-1 agonist, which may cause slightly different nausea patterns in some people, but food choices remain the same: protein, vegetables, hydration, and small portions for both medications.
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.