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
Healthy Diet Plans for Weight Loss
If you're looking to lose weight, the right diet plan can make a real difference. The most effective approach combines a modest calorie deficit with sustainable lifestyle changes. The NHS recommends losing between 0.5 and 1 kg per week for lasting results. This guide covers the main evidence-based diet strategies used in the UK, how they work, and whether prescription weight loss medication might support your goals. Your GP can advise on what suits your individual health needs.
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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.
Evidence-Based Diet Plans That Work
Calorie-deficit dieting: This is the foundation of all weight loss. To lose 0.5 kg per week, you need a deficit of approximately 500 calories per day. The NHS recommends using tools like food tracking apps or online calorie counters to understand your intake. Try our free BMI calculator and weight converter above to establish your current weight status and set a realistic target.
- Mediterranean diet: Strong evidence supports this approach for both weight loss and heart health. Focus on vegetables, whole grains, lean fish, olive oil, and legumes. It's naturally lower in calories whilst being satisfying and sustainable.
- Low-carbohydrate diet: Effective for short-term weight loss, typically resulting in faster initial results than calorie restriction alone. Long-term outcomes are similar to standard calorie-deficit dieting.
- Intermittent fasting (16:8 or 5:2): Evidence suggests these approaches can support weight loss, though results vary. Choose whichever method fits your lifestyle best.
The key is finding a plan you can stick to long-term. Crash diets rarely work — sustainable, modest changes are more effective.
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.
When Diet Alone Isn't Enough
If you've tried diet and lifestyle changes but haven't reached your goals, prescription weight loss medication may help. GLP-1 medications like Wegovy work alongside diet to reduce appetite and support feeling fuller after meals. These are prescription-only and require a clinical assessment. NHS weight loss services, available through your GP, can assess whether medication is appropriate for you. Our free GLP-1 weight loss calculator can help you understand potential outcomes at different doses. Remember: medication works best combined with continued dietary and physical activity changes — it's not a replacement for lifestyle adjustments.
Sustainable weight loss also requires consistent physical activity. The NHS recommends at least 150 minutes of moderate activity per week, plus strength training twice weekly. Track your progress with our free progress tracker to stay motivated. If you have comorbidities like type 2 diabetes or high blood pressure, your GP can refer you to NHS weight management services (Tier 3), where specialist dietary support and medication options are available. Individual needs vary significantly — there's no one-size-fits-all plan. A GP or registered dietitian can provide personalised guidance based on your health status.
- 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.
How many calories should I eat to lose weight?
The NHS recommends a deficit of around 500 calories per day for sustainable loss of approximately 0.5 kg per week. This typically means 1,500–1,800 calories daily for women and 1,900–2,200 for men, though individual needs vary based on activity level and metabolism. Your GP or a registered dietitian can advise on your specific calorie target.
What's the best diet plan for weight loss in the UK?
Evidence supports several approaches: Mediterranean diet, low-carbohydrate diets, calorie-deficit dieting, and intermittent fasting all show effectiveness. The "best" plan is whichever you can sustain long-term. Start with the NHS Weight Loss Plan (free online tool), or ask your GP about referral to weight management services for personalised guidance.
Can I lose weight without changing my diet?
Whilst physical activity is important, sustainable weight loss requires dietary changes. Exercise supports health and can contribute to weight loss, but you cannot outrun a poor diet. The combination of modest calorie reduction plus regular activity is most effective, according to NHS guidance.
Is weight loss medication like Wegovy safe?
GLP-1 medications like Wegovy are prescription-only and licensed in the UK for weight management. They're safe when prescribed by a qualified healthcare professional following a clinical assessment. Side effects are common (nausea, diarrhoea) but usually temporary. Your prescriber will monitor your progress and adjust treatment if needed.
How do I access weight loss support on the NHS?
Start by speaking to your GP, who can assess your eligibility for NHS weight management services. Most areas offer Tier 1 support (self-help tools and community programmes). Specialist services (Tier 2–3) with dietitians and medication options are available based on BMI and comorbidities. Availability varies by region — ask your GP about local services and waiting lists.
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.