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
Mounjaro Friendly Meals — What to Eat and Avoid
When taking Mounjaro (tirzepatide), the right meal choices can help you manage side effects and support your weight loss goals. This UK health guide explains which foods work best alongside your prescription, how to adjust portion sizes as your appetite reduces, and practical meal ideas that fit NHS nutritional guidance. Whether you're in your first weeks on the medication or at a higher dose through dose titration, choosing nourishing, manageable meals makes a real difference to how you feel and your overall progress.
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 and Nutrition Principles on Mounjaro
Mounjaro is a prescription-only medicine, and the right nutrition approach depends on managing side effects like nausea, constipation, and reduced appetite. Start with easily digestible, protein-rich foods that support muscle preservation during weight loss. Good options include lean chicken, fish, eggs, Greek yoghurt, and cottage cheese. Prioritise low-fat options when possible — fatty foods can worsen nausea and stomach discomfort, especially in the first weeks after an injection.
Fibre is important but introduce it gradually. Many people experience constipation on Mounjaro, so adequate water intake and soluble fibre (oats, cooked vegetables, ground flaxseed) help. However, sudden high-fibre foods can cause bloating. Build up slowly over weeks. Include regular vegetables — broccoli, green beans, carrots, spinach — prepared simply (steamed or boiled rather than fried).
- Lean proteins: chicken breast, turkey, white fish, lentils, tofu
- Healthy fats in moderation: olive oil, avocado, nuts (small portions)
- Low glycaemic carbohydrates: brown rice, sweet potato, whole grain bread
- Plenty of water: aim for 6–8 glasses daily to help digestion
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 and Managing Mounjaro Side Effects
Avoid high-fat, greasy, and very spicy foods — these often trigger or worsen nausea when taking Mounjaro. Skip takeaway meals, fried foods, creamy sauces, and heavily processed items during your initial weeks. Reduce sugar and refined carbohydrates as they offer little nutritional value and may cause blood sugar swings. Very large meals are also problematic because Mounjaro slows gastric emptying — your stomach empties more slowly — making you feel uncomfortably full or nauseous.
Eat smaller, regular meals (four to five smaller meals rather than two or three large ones) and chew thoroughly. This approach worked well for many people using NHS specialist weight management services. If you experience side effects that impact your eating, record your meals using our free progress tracker to identify patterns and discuss them with your prescriber at your next review appointment.
- 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 during my first week on Mounjaro?
Start with bland, easily digestible foods: plain chicken, white fish, boiled potatoes, rice, toast, and clear soups. Keep portions small and drink plenty of water. Avoid fatty, spicy, and high-fibre foods for the first few days as your body adjusts. Gradually reintroduce variety from week two onwards as nausea typically improves.
Can I eat normally on Mounjaro?
Not immediately — your appetite will naturally reduce, especially as your dose increases through dose titration. This is the intended effect of the medication. Many people find they feel satisfied with smaller portions. Expect to eat about 40–50% of your previous amount. Your GP or prescriber can advise on nutritional adequacy during this adjustment.
Will Mounjaro cause weight loss if I eat normally?
Mounjaro works alongside a reduced-calorie diet and physical activity — not instead of lifestyle changes. Clinical trials showed that Mounjaro's effectiveness depends on eating less overall. Use our GLP-1 weight loss calculator to estimate your potential results when combined with appropriate nutrition and exercise.
How do I manage constipation while taking Mounjaro?
Increase water intake gradually to 2–3 litres daily, add soluble fibre (cooked vegetables, oats, ground flaxseed) slowly over weeks, and move regularly. Avoid high-fat foods which can worsen constipation. If severe constipation persists, contact your GP — they may recommend a gentle fibre supplement or stool softener suitable for your needs.
What if I can't eat enough to meet my nutritional needs?
Some people struggle to eat enough protein or calories on higher Mounjaro doses. If you're concerned about nutrition, contact your GP or ask for referral to an NHS specialist dietitian. They can assess whether you need dietary supplements or if your dose needs adjustment. Your prescriber reviews your progress regularly.
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.