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 Food Should You Eat While on Mounjaro?
When taking Mounjaro (tirzepatide), your appetite and food tolerance naturally change. This prescription-only injection works by reducing hunger signals and slowing digestion, which means many people find they need less food and may feel nauseous on certain foods. Choosing the right foods during treatment can help you manage side effects, stay nourished, and support sustainable weight loss. This guide covers evidence-based dietary choices for people taking Mounjaro in the UK, alongside reduced-calorie eating and increased physical activity.
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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.
Best Foods to Eat While Taking Mounjaro
When taking Mounjaro, focus on lean proteins, nutrient-dense vegetables, and easily digestible foods. Your reduced appetite means every mouthful should count nutritionally.
- Lean proteins: Chicken breast, turkey, fish, eggs, Greek yoghurt, cottage cheese, tofu — these keep you fuller for longer and support muscle preservation during weight loss
- Non-starchy vegetables: Broccoli, spinach, courgettes, peppers, green beans, asparagus — high in nutrients, low in calories, gentle on digestion
- Whole grains (in small amounts): Brown rice, oats, wholemeal bread — if tolerated; start with tiny portions
- Healthy fats (in moderation): Avocado, olive oil, nuts — nutrient-dense but energy-dense, so portion control matters
- Low-sugar fruits: Berries, apples, oranges — avoid heavy, sugary options that may trigger nausea
Eat slowly, chew thoroughly, and stop when comfortably full — Mounjaro naturally signals fullness sooner than before treatment.
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 or Limit on Mounjaro
Fatty, fried, and heavy foods are common triggers for nausea and discomfort on Mounjaro. Avoid high-fat processed foods, fried takeaway, rich desserts, and fatty meat cuts. High-sugar foods — cakes, sweets, sugary drinks, chocolate — may worsen nausea and undermine weight loss goals. Spicy foods can irritate your stomach; start with mild flavours. Very hot foods and drinks may increase nausea, so try cooler or room-temperature options initially. Alcohol can worsen nausea and dehydration, so limit intake and drink plenty of water. If any food triggers discomfort, note it and avoid that food — individual tolerance varies significantly during Mounjaro treatment.
- 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 normal meals while on Mounjaro?
Your portion sizes will likely be much smaller because Mounjaro reduces appetite. A "normal" pre-Mounjaro meal may now feel overwhelming. Most people find they eat 50–70% less food naturally without hunger. Focus on nutrient-dense foods in smaller portions rather than trying to eat normally.
Will Mounjaro make me feel sick if I eat the wrong foods?
Mounjaro may cause nausea as a side effect, and fatty, fried, or heavy foods often trigger or worsen it. High-sugar and spicy foods can also increase nausea. Start with bland, easily digestible foods and introduce other foods slowly. If something triggers discomfort, avoid it.
Do I need to follow a specific diet while taking Mounjaro?
Mounjaro is most effective alongside a reduced-calorie diet and increased physical activity. There is no single "Mounjaro diet" — focus on whole, nutrient-rich foods in small portions. Your GP or a registered dietitian can provide personalised guidance.
How much should I eat each day on Mounjaro?
There is no set amount — Mounjaro works by reducing your appetite naturally. Listen to your body's hunger signals. Aim for a sustainable calorie deficit (typically 300–500 kcal below your normal intake), and use our GLP-1 weight loss calculator to estimate your potential progress at your specific dose.
What if I cannot eat enough nutrients on Mounjaro?
If you struggle to eat adequate nutrition due to nausea or reduced appetite, speak to your GP. They may recommend smaller, frequent meals, nutritional supplements, or a registered dietitian. Eating too little can slow weight loss and affect health — professional guidance is important.
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.