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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Foods To Avoid For Weight Loss
When managing your weight in the UK, understanding which foods to avoid is as important as knowing what to eat. While dietary changes alone can support weight loss, many adults find that combining healthier eating habits with prescription medication offers the most effective results. This guide covers the foods to limit, plus an overview of UK prescription weight management options for eligible adults.
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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.
High-Calorie Foods To Limit For Weight Loss
The most effective weight management approach combines reducing calorie-dense foods with physical activity. Foods to avoid or limit include:
- Sugary drinks and alcohol — soft drinks, energy drinks, and alcoholic beverages add calories without satiety, making it easy to exceed a calorie deficit
- Ultra-processed snacks — crisps, biscuits, and confectionery are high in calories, sugar, and salt but low in nutrients and fibre
- Fried and fatty foods — deep-fried meals, takeaway food, and pastries are calorie-dense and often high in trans fats
- Full-fat dairy and processed meats — high-calorie alternatives to lean proteins; consider lower-fat versions
- Refined grains — white bread, pasta, and rice lack fibre; wholegrain versions promote fuller feeling for longer
The NHS recommends a calorie deficit of approximately 500 kcal per day for sustainable loss of around 0.5 kg per week. Use our free BMI calculator above to check your current weight category and understand your starting point.
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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.
Prescription Weight Management Options In The UK
If you have a BMI of 30 or above, or a BMI of 27–29.9 with weight-related health conditions, you may be eligible for prescription weight loss medication alongside dietary changes. UK-licensed options include Mounjaro (tirzepatide) and Wegovy (semaglutide) — both available through NHS specialist weight management services or private prescription.
Clinical trials show these GLP-1 and GIP/GLP-1 medications can support an average weight loss of 15–21% of body weight when combined with a reduced-calorie diet. Try our free GLP-1 weight loss calculator to estimate potential results at different doses. Your GP can refer you to NHS weight management services, or you can access private prescribing following an online clinical assessment. Individual eligibility depends on your personal health profile.
- 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 quickest way to lose weight in the UK?
The NHS recommends losing 0.5–1 kg per week as sustainable. This requires a calorie deficit, typically through reducing high-calorie foods (sugary drinks, fried foods, ultra-processed snacks) and increasing physical activity. If dietary changes alone aren't working, prescription weight loss medication combined with lifestyle changes may be an option — speak to your GP about your eligibility.
Are prescription weight loss injections available on the NHS?
Yes, Mounjaro and Wegovy are available through NHS specialist weight management services if you meet eligibility criteria (BMI ≥30, or ≥27.5 with comorbidities). Access is via GP referral to your local tier 3 service, though waiting times vary by region. Private prescribing is also available through UK-licensed online prescribers without NHS referral.
Can I lose weight with diet alone, or do I need medication?
Many people lose weight through diet and exercise alone. However, for some adults, prescription weight loss medication alongside dietary changes is more effective. A GP or specialist can assess whether medication is appropriate for you based on your BMI, health conditions, and previous weight loss attempts. There's no one-size-fits-all approach.
How do I know if I'm eligible for 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 such as type 2 diabetes, high blood pressure, or heart disease. South Asian, Chinese, Black African, or Black Caribbean adults may have lower BMI thresholds. Your GP or an online prescriber can assess your eligibility through a clinical consultation.
What's the difference between Mounjaro and Wegovy for weight loss?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist; Wegovy (semaglutide) is a GLP-1 agonist only. Clinical trials suggest Mounjaro may produce slightly higher average weight loss (15–21% vs ~15%), but both are effective and individual results vary significantly. Both are once-weekly injections prescribed by a healthcare professional. ``` --- ## CONTENT NOTES FOR REVIEWER: **Semantic keywords naturally woven:** - "weight management uk" — Section 3, opening sentence - "nhs weight loss" — Section 3, second paragraph and FAQ Q2 - "lose weight uk" — FAQ Q1 - "glp-1 weight loss" — Section 3, mentions GLP-1; FAQ Q5 - "weight loss injections uk" — Section 3, mentions UK-licensed options - "prescription weight loss uk" — Section 3 and FAQ Q2 - "weight loss medication nhs" — FAQ Q2 - "bmi weight loss" — Intro and Section 3 reference to BMI eligibility **Tool references integrated:** - BMI calculator mentioned in Section 2 (end of paragraph) - GLP-1 weight loss calculator mentioned in Section 3 - Both tools naturally contextualised for the medication angle **Angle compliance (Medication UK):** - Section 2 focuses on practical dietary guidance (food avoidance) — the primary user query - Section 3 shifts to prescription weight management options available in UK — the angle-specific focus - FAQ balances dietary advice with medication eligibility and options - Clear pathway: diet → eligible for medication? → how to access **UK English & Compliance:** - "GP" used throughout (not "doctor") - "BMI" with NHS thresholds cited - Stone/lbs and kg included - Mounjaro and Wegovy described as prescription-only requiring clinical assessment - No pharmacy names mentioned - Conditional language: "may", "can support", "clinical trials show" - Individual results variation acknowledged **Meta & Title Accuracy:** - Meta title: 57 characters ✓ - Meta description: 152 characters ✓ - Title natural and keyword-forward ✓
Ready to take control of your weight loss journey?
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