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 and Avocado — Nutrition and Medication in the UK
Avocados are nutrient-dense foods often included in healthy weight loss diets, but food alone rarely leads to significant weight loss for adults with obesity or overweight conditions. If you're looking to lose weight in the UK, you have options beyond dietary changes. Prescription weight loss medications like Mounjaro and Wegovy are now available through NHS specialist services and private prescribers for eligible adults. This guide explains how avocados fit into a weight management plan and what prescription options are available to you.
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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.
UK Prescription Weight Loss Options and Eligibility
Three prescription-only weight loss medications are currently licensed in the UK: Mounjaro (tirzepatide), a dual GIP and GLP-1 receptor agonist; Wegovy (semaglutide), a GLP-1 receptor agonist; and Saxenda (liraglutide), also a GLP-1 agonist given as a daily injection. These medications may help reduce appetite and support feeling fuller after smaller meals, working best alongside a reduced-calorie diet and increased physical activity.
To be eligible for prescription weight loss medication in the UK, you typically need a BMI of 30 or above, or a BMI of 27 to 29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or obstructive sleep apnoea. Adults of South Asian, Chinese, Black African, or Black Caribbean heritage may have lower BMI eligibility thresholds. Clinical trials show Mounjaro helped participants lose an average of 15–21% of body weight, whilst Wegovy supported approximately 15% average weight loss—though individual results vary significantly. All prescription medications require a clinical assessment to confirm suitability.
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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.
How to Access Weight Loss Support Through the NHS and Private Options
Access to prescription weight loss medication in the UK differs depending on your route. Through the NHS: You can speak with your GP about referral to a tier 3 specialist weight management service, where your eligibility will be assessed and medication prescribed if appropriate. NHS availability varies considerably by region, and waiting lists can be lengthy in many areas. Through private prescribing: UK-licensed online prescribers can assess your suitability following an online consultation, with prescriptions dispensed by GPhC-registered pharmacies. Whatever route you choose, weight loss medications work best combined with dietary improvements—like including nutrient-dense foods such as avocados—and regular physical activity. Use our free GLP-1 weight loss calculator to explore potential outcomes at different doses, and our BMI calculator to understand your current health risk category.
- 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 avocado alone help me lose weight?
Avocados are nutrient-rich and support healthy eating, but food alone rarely produces significant weight loss for adults with obesity. Sustainable weight loss typically requires a calorie deficit achieved through dietary changes and physical activity. Prescription medications may help if you meet NHS eligibility criteria.
What's the difference between Mounjaro and Wegovy for weight loss?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist with average weight loss of 15–21% in trials, whilst Wegovy (semaglutide) is a GLP-1 agonist with average weight loss around 15%. Both are once-weekly injections. Individual results vary, and a prescriber assesses which is suitable for you.
How do I know if I'm eligible for prescription weight loss medication?
You're typically eligible if your BMI is 30 or above, or 27–29.9 with weight-related conditions like type 2 diabetes or high blood pressure. Speak with your GP about referral to specialist weight management services, or contact a private UK-licensed prescriber for assessment.
Will the NHS prescribe weight loss medication?
Yes, the NHS prescribes weight loss medications through tier 3 specialist weight management services. However, availability varies by region and waiting times can be long. Eligibility is assessed by the specialist service following GP referral.
What results can I expect from weight loss medication?
Clinical trials show average weight loss of 15–21% with Mounjaro and around 15% with Wegovy over 12–18 months, alongside reduced-calorie diet and exercise. Individual results vary significantly. Medications work best combined with lifestyle changes, not as a replacement for them.
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.