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 Should You Eat While Taking Mounjaro?
When you start Mounjaro (tirzepatide), your relationship with food changes. You'll likely feel fuller faster and experience reduced appetite, so focusing on nutrient-dense foods becomes essential. The best things to eat on Mounjaro are high-protein options, healthy fats, and plenty of vegetables — foods that keep you satisfied on smaller portions whilst supporting your overall health and wellbeing during weight loss.
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Calculate Your BMI Instantly
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 and Nutrition Tips for Mounjaro Users
The best foods to eat on Mounjaro support your weight loss without causing uncomfortable digestive side effects like nausea or vomiting. Focus on:
- Lean proteins: Chicken, fish, turkey, eggs, tofu, and Greek yoghurt help maintain muscle mass and keep you satisfied longer
- Healthy fats: Avocado, olive oil, nuts, and seeds support nutrient absorption and hormone balance
- Vegetables: Broccoli, leafy greens, peppers, and courgettes are low-calorie, high-fibre options that fill you up without excess calories
- Whole grains: Oats, brown rice, and quinoa provide sustained energy and fibre
- Low-sugar fruits: Berries, apples, and pears offer vitamins without spiking blood sugar
Avoid highly processed foods, sugary drinks, and large fatty meals — these can trigger nausea or indigestion. Many Mounjaro users find that eating smaller, frequent meals works better than three large ones, especially in the first few weeks of treatment.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
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.
How Mounjaro Affects Your Appetite and Eating
Mounjaro works by activating GIP and GLP-1 hormone pathways, which naturally reduce hunger signals and slow gastric emptying — meaning food stays in your stomach longer. This is why portion sizes often reduce dramatically, and why choosing nutrient-dense foods matters more than ever. You may find that foods you previously enjoyed now feel too rich or heavy. This is normal and usually temporary as your body adjusts to the medication.
Many users also experience improved food satisfaction — smaller amounts feel genuinely fulfilling. Try our free GLP-1 weight loss calculator to track your projected progress alongside smart nutrition choices, and our progress tracker to log what foods work best for you and how you feel on each dose.
- 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 in the first week of starting Mounjaro?
Start with bland, easy-to-digest foods: boiled chicken, white rice, toast, plain fish, and broth. Many people experience nausea initially, so simple carbohydrates and lean proteins are easier on the stomach. Avoid fatty, spicy, or rich foods. Stay hydrated and eat smaller portions than usual.
Can I eat normally on Mounjaro or do I need to diet?
You don't need to follow a strict diet, but most people naturally eat less because Mounjaro reduces appetite. However, eating nutrient-dense foods ensures you're getting enough protein, vitamins, and minerals even on smaller portions. Your GP can refer you to a dietitian for personalised guidance if needed.
Will eating certain foods interfere with Mounjaro?
No specific foods block Mounjaro, but high-fat meals, sugary foods, and large portions may trigger nausea or digestive discomfort. Mounjaro slows stomach emptying, so heavy foods linger longer. Choose lighter options like grilled fish, vegetables, and lean meat. If symptoms persist, discuss with your prescriber.
Is it better to have Mounjaro on NHS or private prescription?
NHS Mounjaro is available through specialist tier 3 weight management services but has long waiting lists in many areas. Private online prescriptions offer faster access — you complete an online consultation with a UK-licensed prescriber, and it's dispensed by a GPhC-registered pharmacy. Both require clinical assessment and regular monitoring.
What's the difference between Mounjaro and Wegovy for weight management?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist, whilst Wegovy (semaglutide) is a GLP-1 agonist only. Clinical trials showed Mounjaro resulted in average weight loss of 15–21% body weight, whilst Wegovy showed around 15%. Both are prescription-only and require clinical assessment. Your prescriber will determine which is suitable for you.
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.