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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Weight Loss Meal Plan UK: Medication & Nutrition Guide
A successful weight loss meal plan in the UK works best when combined with the right support — which may include prescription medication for eligible adults. If you're struggling with weight management, understanding your options is crucial. This guide covers nutrition-based approaches alongside prescription weight loss medications available in the UK, including how to access them through the NHS or private prescribing. We'll help you understand what's available and how to find out if you're eligible for treatment that could support your weight loss journey.
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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.
UK-Licensed Prescription Weight Loss Options
If you have a BMI of 30 or above (or 27–29.9 with weight-related health conditions like type 2 diabetes, high blood pressure, or cardiovascular disease), you may be eligible for prescription weight loss medication in the UK. Three GLP-1 and dual GIP/GLP-1 medications are currently licensed:
- Mounjaro (tirzepatide) — dual GIP and GLP-1 receptor agonist, once-weekly injection. Clinical trials showed average weight loss of 15–21% body weight over 72 weeks when combined with diet and exercise.
- Wegovy (semaglutide) — GLP-1 receptor agonist, once-weekly injection. Clinical evidence demonstrated approximately 15% average body weight loss at the maximum dose.
- Saxenda (liraglutide) — GLP-1 receptor agonist, daily injection. Available for adults with BMI ≥30 or ≥27 with comorbidities.
These medications work alongside a reduced-calorie meal plan and increased physical activity — they are not replacements for lifestyle changes. Individual results vary significantly. Our GLP-1 weight loss calculator can help you estimate potential outcomes at different doses, though only a prescriber can assess your personal eligibility.
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.
NHS vs Private Access & How to Start
In the UK, prescription weight loss medication is available through two routes. NHS access is through tier 3 specialist weight management services (usually requiring a GP referral), though availability varies significantly by region and waiting times can be lengthy. Private access is through GPhC-registered online prescribing services following a clinical assessment — this route doesn't require NHS referral and is often faster, though costs apply (typically £129–£320 monthly depending on dose).
To find out if you're eligible, start by calculating your BMI using our free BMI calculator above. If your BMI suggests you may be eligible, speak to your GP about specialist referral or explore private prescribing options. Either way, a licensed prescriber will assess your individual health, medications, and medical history before prescribing. A successful weight management approach combines medication (if appropriate) with a balanced meal plan, regular activity, and ongoing support.
- 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 use weight loss injections without changing my diet?
Weight loss medications like Mounjaro and Wegovy are most effective when combined with a reduced-calorie meal plan and increased physical activity. Medication alone is not recommended as a standalone treatment. These injections support appetite control and help you eat less, but lasting results come from sustainable lifestyle changes alongside medication.
How do I know if I'm eligible for prescription weight loss treatment in the UK?
You may be eligible if your BMI is 30 or above, or 27–29.9 with weight-related health conditions (diabetes, high blood pressure, cardiovascular disease, or sleep apnoea). Use our free BMI calculator to check your BMI, then discuss your options with your GP or a licensed prescriber who can assess your full health profile.
What's the difference between NHS and private weight loss medication in the UK?
NHS access is through specialist tier 3 weight management services (typically slower, no cost to you) while private access is through online prescribing services (faster, costs £129–£320 monthly). Both routes require prescription from a licensed UK prescriber. Medication and clinical evidence are identical — the main difference is access speed and payment method.
How much weight can I expect to lose with Mounjaro or Wegovy?
Clinical trials showed average weight loss of 15–21% body weight with Mounjaro and approximately 15% with Wegovy over 68–72 weeks — alongside a reduced-calorie meal plan and exercise. However, individual results vary significantly. Some people lose more, some less. A prescriber will discuss realistic expectations for your situation.
Do I need a meal plan to start weight loss injections?
Yes. Prescription weight loss medications work best alongside a structured, reduced-calorie meal plan. Your GP or a dietitian can help create a personalised plan. Many people find that medication reduces appetite and cravings, making it easier to stick to a meal plan. Track your progress with our free progress tracker to monitor both weight changes and behaviour changes.
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.