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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How To Break A Weight Loss Plateau
Weight loss plateaus happen to most people trying to lose weight — and they're frustrating but completely normal. Your body adapts to lower calorie intake and increased activity, which means progress can stall even when you're doing everything right. The good news is that plateaus can be broken with strategic changes to your approach, whether through diet, exercise, lifestyle, or—for those who qualify—prescription weight management options available through the NHS and private prescribing in the UK.
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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 Strategies To Restart Weight Loss
A weight loss plateau typically occurs after 6–12 weeks of steady progress, when your body reaches metabolic adaptation. Here are the most effective evidence-based approaches:
- Reassess your calorie intake: As you lose weight, your daily calorie needs decrease. You may need to reduce intake by a further 200–300 kcal or increase activity to maintain your original deficit of 500 kcal/day.
- Change your exercise routine: Your muscles adapt to repetitive exercise. Introduce strength training, vary cardio intensity, or add high-intensity interval training (HIIT) to challenge your body differently.
- Extend fasting windows: If you use intermittent fasting, gradually extend your fasting window by 1–2 hours, or switch from 16:8 to 18:6 timing.
- Increase protein intake: Protein has a higher thermic effect (calories burned digesting it) and helps preserve muscle during weight loss. Aim for 1.6–2.2g per kg of body weight.
- Review sleep and stress: Poor sleep and chronic stress elevate cortisol, which can trigger water retention and appetite increases. Aim for 7–9 hours nightly and use stress management techniques.
These adjustments work best alongside consistent effort over 2–4 weeks before reassessing progress.
Clinically BackedWeight Loss
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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.
When To Consider Prescription Weight Management
If lifestyle changes alone aren't restarting weight loss, prescription weight management medication may help. In the UK, GLP-1 weight loss injections like Wegovy and Mounjaro are available to those who qualify. Our GLP-1 weight loss calculator can help you estimate potential progress at different doses. These work alongside diet and exercise—not instead of them—and may help restart a stalled plateau by reducing appetite and supporting better food choices. Access is through NHS specialist weight management services or private prescribing following clinical assessment. Your GP can discuss whether prescription weight loss medication is appropriate for your specific situation and refer you to specialist services if suitable.
- 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.
Why do weight loss plateaus happen?
Your body adapts to lower calorie intake and increased activity over time. This metabolic adaptation is normal and means your daily energy needs have decreased as you've lost weight. The deficit that created steady progress before is no longer as effective.
How long should I wait before changing my approach?
If your weight hasn't changed for 3–4 weeks despite consistent effort, it's time to reassess. Small fluctuations (±1–2 lbs) due to water retention or hormones are normal, so look for a clear trend rather than daily changes.
Can prescription weight loss injections help break a plateau?
Yes, for those who qualify. GLP-1 medications like Wegovy are prescription-only and may help restart weight loss by reducing appetite and supporting consistent calorie deficit. They require clinical assessment and work best combined with diet and exercise changes.
Should I use the BMI calculator to track progress during a plateau?
Yes. Calculate your BMI regularly using our free BMI calculator—it often shows progress when the scales don't, especially if you're gaining muscle from exercise. Weight alone doesn't reflect body composition changes.
What's a realistic rate of weight loss after breaking a plateau?
The NHS recommends aiming for 0.5–1 kg (1–2 lbs) per week as a sustainable rate. After breaking a plateau, expect 2–3 weeks before seeing consistent progress again as your body adapts to the new changes. ```
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.