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
Weight Loss Eating Plan UK — Creating a Sustainable Approach
A weight loss eating plan in the UK should centre on creating a sustainable calorie deficit whilst maintaining balanced nutrition. The NHS recommends losing weight at a rate of 0.5 to 1 kg per week, which typically requires a reduction of around 500 calories per day. Whether you're managing your weight independently or considering prescription weight loss medication as part of a broader strategy, understanding how to structure your eating plan is essential. This guide covers evidence-based nutrition approaches, meal planning strategies, and how diet works alongside other weight management methods to support your health goals.
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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.
How to Structure a Weight Loss Eating Plan
A sustainable eating plan focuses on whole foods, portion control, and consistent calorie intake rather than restrictive crash diets. The NHS recommends aiming for a deficit of 500 kcal per day to achieve gradual, sustainable weight loss.
- Include protein at every meal — helps you feel fuller longer and preserves muscle mass during weight loss
- Prioritise vegetables and whole grains — high in fibre, low in calories, and nutrient-dense
- Limit processed foods, sugary drinks, and high-calorie snacks — these add calories with minimal nutritional benefit
- Stay hydrated — drinking water before meals can reduce overall calorie intake
- Plan meals in advance — reduces impulsive eating and helps you stay consistent
Research shows that combining dietary changes with increased physical activity produces better long-term results than diet alone. If weight loss isn't progressing with lifestyle changes alone, your GP can discuss prescription weight loss medication options that work alongside healthy eating. Our free BMI calculator can help you track whether your current weight falls within a healthy range for your height.
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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.
Eating Plans and Prescription Weight Loss Support
Prescription weight loss injections like Wegovy (semaglutide) are designed to complement a structured eating plan, not replace it. These GLP-1 medications may help reduce appetite and support feeling fuller after smaller meals, but they work best when combined with sustained dietary changes and increased physical activity.
If you're considering prescription weight loss support, your eating plan remains crucial — medications are a tool to help adherence, not a substitute for nutrition. NHS weight management services include dietary guidance as a core component. Our GLP-1 weight loss calculator can help estimate potential results when medication is combined with diet and exercise. Your GP can assess whether prescription weight management treatment is appropriate for your individual circumstances.
- 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 a realistic calorie target for weight loss in the UK?
The NHS recommends a deficit of around 500 kcal per day for 0.5 kg weekly loss. For most adults, this means a daily intake of 1,500–2,000 kcal, but individual needs vary by age, sex, activity level, and current weight. Your GP or a registered dietitian can provide personalised guidance based on your health profile.
Can I lose weight with diet alone, or do I need exercise?
Diet alone can produce weight loss, but combining dietary changes with physical activity produces better results and helps preserve muscle mass. The NHS recommends both reduced-calorie eating and at least 150 minutes of moderate activity weekly for optimal health outcomes.
Are low-carb diets more effective than calorie reduction?
Research shows that low-carb diets produce similar long-term weight loss to standard calorie restriction — around 0.5–1 kg per week. The most effective plan is one you can stick to consistently. Some people find low-carb approaches help them feel fuller; others prefer balanced macronutrient approaches.
How does prescription weight loss medication fit into an eating plan?
Medications like Wegovy work by reducing appetite and supporting feeling fuller after meals. They're designed to complement dietary changes, not replace them. Evidence shows best results occur when medication is combined with sustained healthy eating and increased physical activity.
What should I do if my weight loss plateaus?
Plateaus are normal and usually temporary. Review portion sizes, ensure you're still in a calorie deficit, increase physical activity, and check for hidden calories in drinks or condiments. If plateaus persist beyond 4 weeks, consult your GP — they can review your approach or discuss whether prescription support might help.
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.