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 Stall — Why Your Progress Has Paused
A weight loss stall, or plateau, happens when your weight stops decreasing despite continuing your diet and exercise routine. This is completely normal and temporary. Your body adapts to reduced calorie intake, metabolism adjusts, and weight loss naturally slows after initial rapid progress. Most plateaus last between 2 to 8 weeks. Understanding why stalls occur and knowing practical strategies to break through them is essential for sustainable weight loss UK success. This guide explains the science behind plateaus and proven methods to restart your progress.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
Why Weight Loss Plateaus Happen
When you first lose weight, your body burns stored energy and water weight decreases rapidly. After several weeks, your metabolism adapts to your lower calorie intake—this is called adaptive thermogenesis. Your body requires fewer calories to maintain its new weight, so the same diet that created initial weight loss no longer produces a calorie deficit. Additionally, as you lose weight, your daily calorie requirements drop because you have less body mass to maintain. For example, an adult weighing 90kg burns more calories at rest than the same person weighing 80kg. Other factors include water retention from hormonal changes, reduced physical activity (intentional or unintentional), hidden calorie increases, and natural metabolic variation. If you're using GLP-1 weight loss medication like semaglutide (Wegovy), plateaus can also occur as your body adapts to the medication—this doesn't mean the treatment has stopped working.
- Metabolic adaptation reduces daily calorie burn
- Body weight decrease lowers energy requirements
- Water retention masks fat loss temporarily
- Hidden calorie increases occur gradually
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.
Evidence-Based Strategies to Break Through a Plateau
Breaking a weight loss plateau requires adjusting your approach. Calculate your new calorie requirements using your current weight—your original target may now be too high. Increase physical activity, particularly strength training, which builds muscle and raises resting metabolic rate. Vary your exercise routine to prevent adaptation. Review your food intake honestly; hidden calories in oils, sauces, drinks, and portion creep are common culprits. Ensure you're eating enough protein (approximately 1.2–2g per kg body weight) to preserve muscle during weight loss. If using prescription weight loss medication like Mounjaro or Wegovy, discuss your plateau with your prescriber—dose adjustment may help. Consider our free GLP-1 weight loss calculator to understand your medication's projected impact. Allow 4–8 weeks before making major changes; some plateaus resolve naturally. Use our progress tracker to log weight, measurements, and progress beyond the scales.
- 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 long does a weight loss plateau typically last?
Most plateaus last 2 to 8 weeks. Some may extend longer if calorie intake matches new energy requirements. This is normal and doesn't mean weight loss has stopped permanently. Patience and strategic adjustments usually restart progress within this timeframe.
Should I eat less calories during a plateau?
Reducing calories further risks muscle loss and metabolic slowdown. Instead, recalculate your calorie needs based on your current weight, review portion sizes for hidden increases, and increase physical activity—especially strength training—to create a deficit without aggressive restriction.
Can weight loss medication help break a plateau?
If you're on prescription weight loss medication like Wegovy or Mounjaro, discuss plateaus with your prescriber. Dose adjustment may help restart weight loss. Clinical trials showed these medications support consistent progress when combined with diet and exercise, but plateaus can still occur as your body adapts.
Does a plateau mean I've reached my goal weight?
Not necessarily. Many people experience multiple plateaus during their weight loss journey before reaching their target. Your GP or use our BMI calculator can help determine your healthy weight range—a plateau doesn't mean you've achieved it if you haven't reached your goal.
What's the best way to track progress during a stall?
When scales don't move, measure other progress: body measurements, how clothes fit, energy levels, and strength improvements. Our free progress tracker helps log these non-scale victories, which are often better indicators of health improvement than weight alone during plateaus.
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.