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
NHS Diets for Weight Loss — Evidence-Based Approaches
The NHS offers several evidence-based diet approaches to support sustainable weight loss and better health outcomes. Rather than promoting a single "diet", the NHS recommends personalised weight management strategies that combine moderate calorie reduction with increased physical activity. Whether you're looking for structured guidance or understanding your options, this guide covers NHS-recommended approaches and when additional support—including prescription weight loss medication—may be appropriate alongside dietary changes.
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.
NHS-Recommended Weight Loss Approaches
The NHS Weight Loss Plan is a free digital programme designed to help UK adults lose weight sustainably. It focuses on reducing calorie intake by approximately 500 calories per day, which typically results in a weight loss of 0.5–1 kg per week. The NHS recommends losing weight gradually rather than rapidly, as this approach is more sustainable and helps preserve muscle mass.
- Calorie deficit: Aiming for 1,200–1,500 kcal per day for women and 1,500–1,900 kcal per day for men, depending on current weight and activity level
- Balanced nutrition: Emphasis on whole grains, lean proteins, vegetables, and healthy fats rather than restrictive elimination
- Behaviour change: The NHS Weight Loss Plan includes digital coaching focused on habit change, emotional eating awareness, and sustainable lifestyle shifts
- Physical activity: Combining dietary changes with 150 minutes of moderate-intensity activity per week (or 75 minutes of vigorous activity)
You can access the NHS Weight Loss Plan through your GP practice or via the NHS Every Body Can programme, which is available free to eligible patients.
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.
Weight Management Beyond Diet Alone
For many people, weight loss depends on factors beyond diet alone—including medical conditions, medications, genetics, and psychological factors. If lifestyle changes and the NHS Weight Loss Plan haven't produced the desired results, your GP can refer you to a specialist weight management service (tier 3 NHS care). These services may offer structured programmes, behavioural therapy, and access to prescription weight loss medications for eligible adults.
Eligibility for NHS prescription weight loss medication typically requires a BMI of 30 or above, or 27 or above alongside weight-related health conditions such as type 2 diabetes, hypertension, or cardiovascular disease. Check your personal BMI using our free BMI calculator above to understand where you fall on the NHS guidance range.
Prescription weight loss medications—including GLP-1 receptor agonist injections—are only available through NHS specialist weight management services and are always used alongside continued dietary and lifestyle changes, never as a replacement. Access, waiting times, and availability vary significantly across UK regions (Integrated Care Boards). For those who cannot access NHS services or prefer faster access, private prescribing through a UK-licensed prescriber and GPhC-registered pharmacy is also available in the UK. Track your progress and stay motivated by logging your weight changes using our free progress tracker.
- 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 is the NHS recommended rate of weight loss?
The NHS recommends losing 0.5–1 kg (1–2 lbs) per week as a safe, sustainable rate. This typically requires a calorie deficit of around 500 kcal per day. Faster weight loss is possible but increases the risk of muscle loss and nutrient deficiencies. Very gradual weight management should only be pursued under medical supervision.
Is the NHS Weight Loss Plan free?
Yes, the NHS Weight Loss Plan is completely free and available to eligible UK adults through participating GP practices and the NHS Every Body Can programme. It combines digital coaching with personalised calorie and activity guidance. Ask your GP whether you're eligible or access it directly through the NHS website.
When should I consider prescription weight loss medication?
Prescription weight loss medication may be considered if you have a BMI of 30 or above (or 27 with weight-related health conditions), and lifestyle changes alone haven't achieved adequate results. Your GP can assess your individual eligibility and refer you to a specialist NHS weight management service, where medication options are reviewed.
Can I use our GLP-1 weight loss calculator to estimate results?
Yes, our free GLP-1 weight loss calculator on this page can help you estimate potential weight loss at different doses of prescription medications, based on clinical trial data. However, individual results vary significantly. Always consult your GP or a licensed prescriber before considering prescription weight loss treatment.
What's the difference between weight loss diets and weight management?
Weight loss diets often focus on short-term restriction, while the NHS approach emphasises sustainable weight *management*—building healthy habits, understanding triggers, and making lasting lifestyle changes. This approach is more effective long-term and supports overall health, not just the number on the scales.
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.