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 I Eat When Taking Mounjaro?
When taking Mounjaro (tirzepatide), the medication itself reduces appetite and food cravings, but what you choose to eat still matters significantly. A balanced, nutritious approach alongside the injection helps maximise results, manage side effects like nausea, and support your overall health. This guide covers practical eating strategies for Mounjaro users in the UK, based on how the medication works and common experiences reported in clinical practice.
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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 and Eating Strategies on Mounjaro
Mounjaro is a dual GIP and GLP-1 receptor agonist that slows how quickly food leaves your stomach and reduces hunger signals. This means you'll naturally eat less, so nutrient density matters more than quantity. Prioritise protein-rich foods: lean meats, fish, eggs, Greek yoghurt, and pulses help preserve muscle during weight loss and promote satiety. Include plenty of non-starchy vegetables—broccoli, spinach, peppers, courgettes—as they're low in calories and high in fibre, supporting digestion and fullness.
- Whole grains: oats, brown rice, and wholemeal bread in modest portions
- Healthy fats: avocado, olive oil, nuts in small amounts—they slow gastric emptying and aid nutrient absorption
- Hydration: drink plenty of water throughout the day; many users confuse thirst with hunger
- Smaller, frequent meals: eat every 3–4 hours rather than large meals, which may trigger nausea
Start each meal with protein or fibre to stabilise blood sugar and enhance satiety. Your GP or a registered dietitian can provide personalised meal planning tailored to your health profile and eligibility for Mounjaro.
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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
Avoid or limit: high-fat, fried, and heavily processed foods, which can trigger nausea and digestive discomfort—common side effects when starting Mounjaro. Sugary drinks, sweets, and refined carbohydrates offer little nutritional value and may cause blood sugar spikes. Spicy foods and caffeine can exacerbate nausea in the first few weeks.
If you experience nausea, eat bland, easily digestible foods: plain rice, plain chicken, toast, bananas, and ginger tea. Keep meals small and cool (chilled foods are sometimes better tolerated). Avoid eating too quickly; slow, mindful eating reduces bloating. If nausea persists beyond a few weeks or side effects worsen, contact your GP—dose adjustment or additional support may help.
- 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?
You'll likely feel fuller faster and have reduced appetite, so portion sizes naturally decrease. You don't need to follow a strict diet, but choosing nutrient-dense foods—protein, vegetables, whole grains—ensures you meet your nutritional needs despite eating less. Your GP can advise on personalised nutrition.
Do I need to count calories on Mounjaro?
Calorie counting isn't essential because Mounjaro suppresses appetite naturally, but being aware of food choices helps. Focus on nutrient quality rather than strict counting. Our free GLP-1 weight loss calculator can help you estimate projected outcomes alongside healthier eating habits.
What if I feel nauseous after eating?
Nausea is common in the first few weeks on Mounjaro. Eat smaller meals, avoid fatty or spicy foods, and try bland options like plain rice or chicken. Sip water slowly between meals rather than during them. If nausea persists beyond 4 weeks or severely impacts eating, contact your GP—dose adjustment may be needed.
Is alcohol safe while taking Mounjaro?
Alcohol is not contraindicated, but Mounjaro slows gastric emptying, potentially intensifying alcohol effects. Drink moderately and with food. Alcohol is also calorie-dense and may hinder weight loss goals. Always discuss alcohol consumption with your prescriber if you have health concerns.
Should I take supplements on Mounjaro?
Because you're eating less, a basic multivitamin may be beneficial to cover any micronutrient gaps—particularly B12, iron, and calcium. Discuss supplementation with your GP or a registered dietitian to ensure it's appropriate for your individual health needs and any existing conditions.
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.