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 Meals Should You Eat on Mounjaro?
If you're taking Mounjaro (tirzepatide), you may find that your appetite is naturally reduced and your approach to meals changes significantly. This guide explains how to eat well on Mounjaro, what meal patterns work best, and how to manage common side effects like nausea and stomach discomfort. Mounjaro is a prescription-only injection that works by reducing hunger signals and slowing how quickly food leaves your stomach. Understanding how to structure your meals around these changes helps you stay nourished while losing weight effectively alongside the medication.
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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 Meal Approaches While on Mounjaro
When starting Mounjaro (tirzepatide), most people naturally eat smaller portions without forcing themselves. Your meals may look very different from before — this is normal and expected. Here are meal patterns that tend to work well:
- Smaller, frequent meals: Instead of three large meals, try four to five smaller eating occasions throughout the day
- Protein-focused meals: Prioritise protein at each meal — it keeps you satisfied longer and supports muscle preservation during weight loss. Aim for chicken, fish, eggs, lean meat, Greek yoghurt, or legumes
- Eat slowly: Mounjaro slows your digestion, so eating slowly gives your body time to register fullness. Put your fork down between bites
- Hydration: Drink water consistently throughout the day — dehydration can worsen nausea. Aim for 2–3 litres daily unless your GP advises differently
- Nutrient density over volume: Choose whole foods over highly processed options. Your smaller portions mean every calorie should count nutritionally
Many people find they naturally skip meals or forget to eat on Mounjaro — this is the medication working as intended, but ensure you're still meeting basic nutritional needs.
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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.
Managing Side Effects and Meal Timing
Nausea, diarrhoea, and stomach discomfort are common side effects of Mounjaro, especially when starting or increasing doses. Meal timing and food choices can help minimise these:
- Avoid greasy, fried, or high-fat foods: These worsen nausea and digestive upset. Choose grilled, baked, or steamed options instead
- Limit sugary foods and drinks: Excess sugar can trigger nausea and doesn't align with weight loss goals
- Ginger, peppermint tea, and bland foods: If nausea strikes, ginger biscuits, peppermint tea, crackers, or toast may help settle your stomach
- Meal spacing: Leave 2–3 hours between eating and lying down to reduce reflux and stomach discomfort
- Track what triggers symptoms: Keep a simple food diary for a week — this helps identify which foods make you feel worse
If side effects persist beyond a few weeks or significantly impact your ability to eat, speak to your GP or the prescriber who issued your Mounjaro prescription.
- 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?
No — most people eat significantly less on Mounjaro because the medication reduces appetite. You'll naturally feel full with smaller portions. This is the intended effect. You don't need to force yourself to eat large meals; instead, focus on nutritious smaller portions that meet your daily nutritional needs.
What foods should I avoid on Mounjaro?
Avoid high-fat fried foods, very sugary items, large heavy meals, and foods you know trigger nausea or stomach upset. Alcohol can worsen nausea and dehydration. These aren't forbidden, but they often cause discomfort on tirzepatide. Stick to protein-rich, nutrient-dense whole foods when possible.
Will I lose weight faster if I eat less on Mounjaro?
Not necessarily. Eating too little can slow your metabolism, cause muscle loss, and make the medication less effective long-term. Aim for a moderate calorie deficit (around 500 kcal below your normal intake) alongside Mounjaro. Use our free GLP-1 weight loss calculator to estimate realistic outcomes at your dose.
How much should I eat per meal on Mounjaro?
There's no set amount — it depends on your body and how much the medication is affecting your appetite. Most people find they're satisfied with 200–400 kcal per meal initially, increasing as they adjust. Focus on feeling comfortably full rather than eating a specific amount. Your GP can advise if you're concerned about intake.
Is it normal to forget meals on Mounjaro?
Yes, this is very common. Mounjaro significantly reduces appetite signals. However, try to eat something nutritious at least twice daily to maintain energy and muscle mass. If you're struggling to eat enough or losing weight too rapidly (more than 1 kg per week consistently), speak to your prescriber or GP.
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.