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
What's the Best Weight Loss Plan in the UK?
There's no single "best" weight loss plan for everyone — the most effective approach depends on your health, lifestyle, BMI, and personal preferences. However, evidence-based strategies combined with professional support offer the strongest results. The NHS recommends sustainable weight management involving dietary changes, increased physical activity, and behavioural support. For some people, prescription weight loss medication may also be appropriate. This guide explores evidence-based weight loss approaches available in the UK, from self-managed plans to specialist medical support.
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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.
Understanding Effective Weight Loss Approaches
The most successful weight loss plans share common elements: a sustainable calorie deficit, regular physical activity, behavioural change, and professional support. The NHS recommends losing weight at a rate of 0.5 to 1 kg per week, which is safe and sustainable. This typically requires a daily calorie deficit of around 500 kcal.
- Calorie deficit diets: Creating a modest deficit through reduced-calorie eating is the foundation of most successful plans. Research shows this works regardless of the specific diet type (low-carb, Mediterranean, etc.).
- Structured programmes: NHS Weight Loss Plan, Weight Watchers, and similar programmes combine education, tracking, and community support — this structure improves adherence and results.
- Physical activity: Regular exercise (150 minutes moderate activity weekly) supports weight loss and maintenance whilst preserving muscle mass.
- Behavioural support: Evidence shows that counselling, habit tracking, and accountability significantly improve long-term success rates compared to diet alone.
Even a 5–10% reduction in body weight delivers meaningful health benefits including improved blood pressure, better blood sugar control, and reduced joint strain.
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 Weight Loss Pathway and Prescription Options
The NHS offers a structured four-tier weight management pathway. Tier 1 involves self-help and digital tools (including our free BMI calculator and progress tracker to monitor your journey). Tier 2 includes primary care-based behaviour change programmes and community weight management services. Tier 3 provides specialist multidisciplinary services where prescription medications may be considered. For eligible adults, prescription weight loss medication — such as GLP-1 injections like Wegovy (semaglutide) or Mounjaro (tirzepatide) — may support weight management alongside lifestyle changes. These medications require a prescription, clinical assessment, and ongoing monitoring. Tier 4 covers bariatric surgery for severe obesity with significant health complications.
- 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 makes a weight loss plan "effective"?
An effective plan creates a sustainable calorie deficit (typically 500 kcal/day for ~0.5 kg/week loss), includes regular physical activity, provides behavioural support, and aligns with your lifestyle. Evidence shows structured programmes with accountability have higher success rates than unguided dieting. Use our BMI calculator to establish your starting point and track progress.
What is the recommended safe rate of weight loss in the UK?
The NHS recommends losing no more than 0.5 to 1 kg (1–2 lbs) per week. This rate is sustainable, preserves muscle mass, and is less likely to cause nutritional deficiencies or gallstones. Faster weight loss is possible with medical supervision but carries increased risks.
Can prescription weight loss medication help me lose weight?
Yes — for eligible adults, prescription medications like Wegovy (semaglutide) may support weight loss. Clinical trials show GLP-1 injections can help with an average weight loss of 14–20% of body weight alongside reduced-calorie diet and exercise. These medications require a prescription and individual clinical assessment. Our GLP-1 weight loss calculator can help estimate potential results.
How do I access weight loss support through the NHS?
Start by speaking with your GP, who can assess your weight, health, and eligibility. Your GP can refer you to tier 2 community services (e.g., NHS Weight Loss Plan) or tier 3 specialist weight management services if appropriate. Waiting times and availability vary by region. Private online prescribing is also available without NHS referral.
Which weight loss plan is best — low-carb, Mediterranean, or calorie counting?
Research shows that various diet types (low-carb, Mediterranean, intermittent fasting, calorie-restricted) all produce similar weight loss when a calorie deficit is maintained. The "best" plan is the one you can sustain long-term. Mediterranean-style eating has the strongest evidence for cardiovascular health alongside weight loss.
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.