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
Best Foods For Quick Weight Loss in the UK
While certain foods can support weight loss — like high-protein options, whole grains, and vegetables — sustainable results require a calorie deficit alongside lifestyle changes. For eligible UK adults, prescription weight management options like Mounjaro and Wegovy are also available alongside dietary changes. This guide covers both food choices and medication-based approaches to losing weight in the UK, plus how to find out if you qualify for NHS weight loss support.
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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.
Foods that support weight loss and medication options in the UK
Best foods for weight loss include:
- Lean proteins (chicken, fish, eggs) — increase satiety and preserve muscle during weight loss
- Whole grains (oats, brown rice, quinoa) — slower digestion means longer fullness
- Vegetables (broccoli, spinach, peppers) — high volume, low calories
- Legumes (lentils, beans) — protein-rich and filling
- Berries and fruit — nutrient-dense with natural fibre
- Nuts and seeds — healthy fats that support satiety
The NHS recommends a sustainable approach: aim for a calorie deficit of around 500 kcal per day, which typically results in losing approximately 0.5–1 kg per week. Quick weight loss is possible but often leads to muscle loss and weight regain. For eligible adults in the UK, GLP-1 weight loss injections like Mounjaro and Wegovy can complement dietary changes by reducing appetite and supporting weight management. Try our free GLP-1 weight loss calculator to see potential outcomes at different doses if you're considering prescription options.
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 weight loss support and prescription medication eligibility
The NHS weight loss pathway starts with your GP. If you have a BMI of 30 or above — or BMI of 27 or above with weight-related health conditions like type 2 diabetes, high blood pressure, or heart disease — you may be eligible for specialist support. This can include referral to tier 3 weight management services where prescription medications such as tirzepatide (Mounjaro) or semaglutide (Wegovy) may be considered. Private prescription weight loss medication is also available in the UK through online clinical assessments, often with shorter waiting times. Check your BMI instantly using our free BMI calculator, then speak with your GP about your options for NHS weight loss support or ask about private alternatives.
- 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's the fastest safe way to lose weight?
The NHS recommends losing 0.5–1 kg per week through a combination of dietary changes, increased physical activity, and reduced calorie intake. Very gradual weight management often leads to muscle loss and nutritional deficiencies. Prescription weight management medications like Mounjaro may accelerate results when used alongside lifestyle changes, but individual results vary.
Can I use weight loss injections alongside a diet?
Yes — prescription weight loss medications like Wegovy and Mounjaro are designed to be used alongside a reduced-calorie diet and increased physical activity. They're not replacements for lifestyle changes but support tools. Your prescriber will give you specific guidance on combining medication with dietary adjustments.
How do I know if I'm eligible for NHS weight loss medication?
Eligibility typically requires a BMI of 30 or above, or 27 or above with weight-related health conditions. Contact your GP to discuss your options — they can assess whether you qualify for specialist referral or prescription treatment. Availability varies by region in the UK.
Are weight loss foods effective without exercise?
Food choices alone can support modest weight loss, but the NHS recommends combining dietary changes with physical activity for best results and long-term sustainability. Exercise also preserves muscle mass during weight loss and improves cardiovascular health.
What's the difference between Mounjaro and Wegovy for weight loss?
Both are prescription-only UK-licensed injections. Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist with an average weight loss of 15–21% in clinical trials. Wegovy (semaglutide) is a GLP-1 agonist with average weight loss around 15%. Individual results vary. Your prescriber will recommend the most suitable option for you.
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.