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 To Eat On Mounjaro — Practical Food Guidance
When taking Mounjaro (tirzepatide) for weight loss, your appetite naturally decreases, which is how the medication works. However, eating the right foods ensures you still get adequate nutrition, manage side effects like nausea and constipation, and sustain energy levels. This guide covers practical dietary strategies for UK adults taking this prescription weight loss injection, alongside a reduced-calorie diet and increased physical activity as recommended by NICE and NHS specialists.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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 To Eat On Mounjaro
On Mounjaro, focus on nutrient-dense, protein-rich foods that keep you satisfied on smaller portions. Lean proteins (chicken breast, turkey, fish like salmon and mackerel, eggs) should form the foundation of most meals — aim for 20–30g per meal. These support muscle preservation during weight loss and help manage hunger signals.
Non-starchy vegetables are essential: leafy greens, broccoli, cauliflower, courgettes, peppers, and green beans are low-calorie, high-fibre, and gentle on the digestive system. Aim to fill half your plate with vegetables. Whole grains in moderation (brown rice, oats, quinoa) provide sustained energy without spiking blood sugar.
Healthy fats from avocados, nuts, seeds, and olive oil support nutrient absorption and satiety. Dairy products like Greek yoghurt offer protein and probiotics, which may help with digestive health. Start portions small — Mounjaro reduces appetite, so you'll likely feel full on less food than before.
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.
Foods To Avoid Or Limit On Mounjaro
Ultra-processed foods, high-sugar items, and fatty takeaways are more likely to trigger nausea, stomach pain, and reflux whilst on Mounjaro — these side effects are common during the first few weeks. Avoid sugary drinks, cakes, biscuits, and fried foods. Spicy foods may worsen reflux in some people.
Large meals are difficult to tolerate; your stomach empties more slowly on Mounjaro, which can cause discomfort. Instead, eat smaller, frequent meals (4–5 per day). Alcohol is not forbidden but should be limited — it may increase nausea and is high in empty calories. Carbonated drinks can cause bloating. If you're experiencing constipation (very common on Mounjaro), increase fibre gradually through vegetables and stay hydrated with water.
- 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?
Your appetite will naturally decrease on Mounjaro, so portion sizes typically become much smaller automatically. You may find you can't eat as much as before — this is expected. Focus on nutrient-dense foods rather than calorie counting. Listen to your hunger signals.
Does Mounjaro cause nausea with food?
Yes, nausea is very common, especially when starting or increasing doses. Eat small meals, avoid fried and greasy foods, and stay hydrated. Most users report nausea improves after a few weeks as their body adjusts. If severe, speak to your prescriber.
How much protein do I need on Mounjaro?
Aim for 20–30g of protein per meal to preserve muscle during weight loss and maintain satiety on smaller portions. Good sources include chicken, fish, eggs, Greek yoghurt, and legumes. This is especially important alongside a reduced-calorie diet.
What should I do if Mounjaro causes constipation?
Increase fibre gradually through vegetables, whole grains, and flaxseed. Drink plenty of water (at least 2 litres daily) and consider a fibre supplement if needed. Physical activity also helps. If constipation persists, discuss options with your GP — you may need a mild laxative.
Can I use our GLP-1 weight loss calculator to plan my meals?
Our weight loss calculator estimates potential weight loss projections on Mounjaro at different doses. Combined with the BMI calculator to track your starting point and progress, and our progress tracker to log meals and weight changes, you can monitor how your food choices support your weight loss goals alongside your medication. ```
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.