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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Diet Table For Weight Loss in the UK
A diet table for weight loss provides a structured calorie breakdown to support sustainable weight management. In the UK, if you're overweight or obese, you have several options: lifestyle changes including reduced-calorie diets, NHS weight loss programmes, or prescription weight management medication. This guide covers UK-licensed options including GLP-1 injections like Mounjaro and Wegovy, NHS access routes, and how to determine if prescription weight loss medication is right for you. Use our free BMI calculator above to check your starting point and explore what weight management support is available.
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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 a BMI of 27–29.9 with weight-related health conditions (type 2 diabetes, high blood pressure, sleep apnoea, or cardiovascular disease), you may be eligible for prescription weight loss medication in the UK.
Three main options are licensed for weight management:
- Mounjaro (tirzepatide) — once-weekly injection, dual GIP/GLP-1 mechanism. Clinical trials showed average weight loss of approximately 15–21% body weight.
- Wegovy (semaglutide) — once-weekly GLP-1 injection. Average weight loss approximately 14.9% body weight in trials.
- Saxenda (liraglutide) — daily GLP-1 injection. Average weight loss approximately 5–10% body weight.
All three are prescription-only and require a clinical assessment before being prescribed. Medication works best alongside a reduced-calorie diet and increased physical activity — the diet table approach combined with injectable support.
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 in the UK
NHS route: Referral from your GP to a tier 3 specialist weight management service. Access varies significantly by region — some areas have long waiting lists. Once assessed, specialist services may prescribe medication as part of a comprehensive weight loss programme.
Private route: Online prescription services offer faster access. Following a clinical assessment with a UK-licensed prescriber, medication can be dispensed by a GPhC-registered pharmacy. Costs typically range from £129–£320 monthly depending on dose and provider.
Whichever route you choose, speak to your GP first. They can assess your health, confirm eligibility, discuss options, and refer you to NHS services if appropriate. Try our GLP-1 weight loss calculator to estimate potential outcomes at different medication doses, and use the weight converter and progress tracker to monitor your journey.
- 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 a diet table for weight loss, and do I need medication?
A diet table is a structured calorie breakdown guiding daily food intake for weight loss. Diet alone works for many people — aim for a 500 kcal daily deficit for approximately 0.5 kg weekly loss. Prescription medication like Mounjaro or Wegovy may be recommended if you have a BMI of 30+ or 27+ with health conditions, and diet and exercise alone haven't worked. Your GP can advise.
How do I know if I'm eligible for prescription weight loss medication in the UK?
You may be eligible if you have a BMI of 30 or above, or 27–29.9 with weight-related health conditions (diabetes, high blood pressure, sleep apnoea, heart disease). South Asian, Chinese, Black African, and Black Caribbean adults may have lower thresholds. Book a GP appointment to discuss your individual circumstances and eligibility.
What's the difference between Mounjaro and Wegovy for weight loss?
Mounjaro (tirzepatide) uses dual GIP/GLP-1 action and achieved average weight loss of 15–21% in trials. Wegovy (semaglutide) is GLP-1 only, with average weight loss around 14.9%. Both are once-weekly injections. Results vary individually. A prescriber will choose the best option based on your health profile and medical history.
Can I get prescription weight loss medication on the NHS in the UK?
Yes. NICE has approved tirzepatide (Mounjaro) and other GLP-1 medications for NHS specialist weight management services. Access is through tier 3 services — your GP can refer you. Availability and waiting times vary by region. Private prescription services offer faster access if you meet eligibility criteria and choose to pay privately.
What's the safest rate of weight loss per week in the UK?
The NHS recommends losing 0.5–1 kg (1–2 lbs) per week for sustainable, safe weight loss. This typically requires a calorie deficit of approximately 500 kcal per day. Faster loss is possible with medical support but increases muscle loss risk. Use our progress tracker to monitor your rate of loss and consult your GP if losing faster than 1.5 kg weekly. ```
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.