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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Mounjaro Diet Plan: Nutrition Guide for UK Users
A Mounjaro diet plan isn't about a specific restrictive menu—it's about eating smaller portions and choosing nutrient-dense foods that work with how the medication affects your appetite. Mounjaro (tirzepatide) is a prescription-only GIP and GLP-1 receptor agonist injection that helps you feel fuller faster and reduces cravings. When combined with mindful eating, most people find they naturally eat less without feeling deprived. This guide explains what to eat, how Mounjaro changes your relationship with food, and how to make dietary changes sustainable while using this 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.
How Mounjaro Changes Your Eating Habits
Mounjaro works by activating two hormone pathways—GIP and GLP-1—that signal to your brain that you're full. This means you'll likely eat smaller portions without feeling hungry. Many people report that food cravings disappear, especially cravings for fatty or sweet foods. Your appetite naturally decreases, not through willpower but through the medication's effect on your gut and brain.
The medication also slows how quickly food leaves your stomach (gastric emptying), which helps you feel satisfied longer. As your dose increases from 2.5 mg to 15 mg, this effect typically becomes stronger, though it often plateaus after a few weeks on each dose.
What this means for diet: You don't need a special "Mounjaro diet"—instead, focus on eating high-protein, high-fibre foods in smaller quantities. Nausea is common early on, so soft, easily digestible meals work better initially. Staying hydrated is essential, as constipation can occur.
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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.
Best Foods and What to Avoid on Mounjaro
Foods that work well: Lean proteins (chicken, fish, turkey, eggs), Greek yoghurt, cottage cheese, vegetables (especially non-starchy), oats, beans, lentils, nuts, and wholegrain bread. These keep you full longer and support your weight loss. Protein is especially important—aim for 25–30g per meal—because it helps preserve muscle mass during weight loss and complements how Mounjaro works.
Foods to limit or avoid: Fatty, greasy, or fried foods often trigger nausea when you're on Mounjaro. Very sugary foods may cause symptoms similar to dumping syndrome. Alcohol can worsen nausea and dehydration. Extremely large meals are difficult because Mounjaro reduces your appetite—eating slowly and stopping when comfortably full prevents discomfort. Try our GLP-1 weight loss calculator to track how dietary changes combine with your Mounjaro dose for projected weight loss outcomes.
- 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.
Do I need a specific Mounjaro diet plan?
No—Mounjaro works best with a balanced, sustainable diet rather than a restrictive plan. Focus on high-protein, high-fibre foods in smaller portions. Because Mounjaro reduces your appetite, you'll naturally eat less without needing to "diet" intensely. Your GP or a dietitian can provide personalised advice based on your health.
Will I feel hungry on Mounjaro?
Most people report significantly reduced hunger and food cravings on Mounjaro, especially as doses increase. Hunger may return if you miss a dose or once you stop the medication. Some people find they forget to eat because appetite suppression is so effective. Eating regular, balanced meals ensures adequate nutrition.
What if I feel nauseous when eating?
Nausea is a common side effect early on and often improves over time. Eat soft, bland foods like porridge, scrambled eggs, soup, or mashed vegetables. Avoid fatty, spicy, or very sweet foods. Eat slowly and in smaller portions. Stay hydrated. If nausea persists beyond a few weeks, contact your GP—dose adjustment may help.
How much weight can I expect to lose with diet and Mounjaro?
Clinical trials showed average weight loss of 15–21% of body weight at the highest dose (15 mg), alongside a reduced-calorie diet and physical activity. Individual results vary significantly. Use our GLP-1 weight loss calculator to estimate potential outcomes at different doses. Your actual results depend on diet quality, exercise, consistency, and genetics.
Can I drink alcohol on Mounjaro?
Alcohol can worsen nausea and dehydration, which are already common side effects. If you do drink, do so moderately and with food. Alcohol is also calorie-dense and may slow weight loss. Discuss alcohol use with your prescriber, especially if you have any underlying health conditions or take other medications.
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.