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
Creating an Effective Eating Weight Loss Plan
An eating weight loss plan combines dietary changes with sustainable habits to help you lose weight safely. The NHS recommends losing 0.5 to 1 kg per week for lasting results. This guide covers evidence-based eating strategies, how to calculate your calorie needs, and when prescription weight loss medication might support your plan. Whether you're looking to lose weight through diet alone or exploring additional support, understanding the fundamentals helps you make informed choices about your health.
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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.
Core Components of a Sustainable Eating Plan
A successful eating weight loss plan starts with understanding your calorie deficit — eating fewer calories than your body burns. A deficit of around 500 kcal per day typically results in approximately 0.5 kg weight loss per week. Begin by calculating your baseline calorie needs (your age, height, weight, and activity level all affect this). You can then create a modest deficit by reducing portion sizes, choosing lower-calorie alternatives, or increasing physical activity.
- Mediterranean diet: Strong evidence supports this approach for both weight loss and cardiovascular health
- Low carbohydrate diet: Effective short-term; long-term outcomes are similar to standard calorie restriction
- Intermittent fasting (16:8 or 5:2): Evidence shows modest weight loss results
- Balanced whole foods: Prioritise protein, fibre, and vegetables — these support satiety and sustainable eating
Track your eating using our free BMI calculator to monitor your weight progress and adjust your plan if needed. The key is finding an approach you can maintain long-term, not a restrictive diet you'll abandon.
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 UK: When to Consider Additional Support
If you've tried dietary changes and need additional support, several options are available through the NHS weight loss pathway. Your GP can refer you to a specialist weight management service, where you may discuss prescription weight loss medication if you have a BMI of 30 or above, or 27 or above with weight-related health conditions like type 2 diabetes or high blood pressure. Prescription weight loss injections such as GLP-1 medications may help reduce appetite and support your eating plan when used alongside dietary changes. Try our GLP-1 weight loss calculator to estimate potential outcomes at different doses. Remember that prescription medications require a clinical assessment and are prescribed only when appropriate for your individual 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 best eating plan for weight loss?
The best plan is one you can sustain long-term. Evidence supports the Mediterranean diet, calorie-controlled eating, and balanced whole foods. The NHS recommends a 500 kcal daily deficit for approximately 0.5 kg weekly loss. Choose a structured approach that fits your lifestyle, preferences, and health needs.
How many calories should I eat to lose weight?
This depends on your individual baseline (age, height, weight, activity level). Generally, reducing intake by 500 kcal per day creates sustainable weight loss of about 0.5 kg per week. Your GP or a dietitian can calculate your specific needs and safe calorie range — avoid very low calorie diets without medical supervision.
Can an eating plan alone help me lose weight?
Yes, many people lose weight through dietary changes alone. However, combining eating changes with increased physical activity is more effective and supports muscle retention. If you've tried diet and exercise without sufficient progress, your GP can discuss prescription weight loss medication options.
What's the difference between weight loss injections and diet alone?
GLP-1 weight loss injections like semaglutide may help reduce appetite and food cravings when combined with an eating plan. Clinical trials showed average weight loss of around 15% body weight. Injections are prescription-only and require clinical assessment — they support diet and exercise, not replace them.
How quickly can I expect to lose weight?
The NHS recommends 0.5 to 1 kg per week for safe, sustainable loss. Faster loss is possible with medical support but increases muscle loss risk. Use our progress tracker to log weekly weight and identify trends — small weekly variations are normal; focus on the longer-term direction instead.
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.