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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Weight Loss Fitness Program — What Works in the UK
A successful weight loss fitness program combines regular physical activity with dietary changes and, where appropriate, medical support. The NHS recommends losing weight at a rate of 0.5 to 1 kg per week for sustainable results. Fitness alone rarely produces significant weight loss without calorie reduction, but exercise plays a crucial role in preserving muscle mass, improving cardiovascular health, and supporting long-term weight management. This guide covers evidence-based approaches to weight loss through fitness in the UK context, including how prescription weight management options may fit into your overall programme.
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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.
How Fitness Contributes to Weight Loss
Physical activity supports weight loss in several ways. Cardiovascular exercise (running, cycling, swimming) burns calories during the activity itself. Resistance training builds muscle, which increases your resting metabolic rate — meaning you burn more calories throughout the day even at rest. A combination of both is most effective.
- The NHS recommends at least 150 minutes of moderate-intensity aerobic activity per week (or 75 minutes vigorous-intensity)
- Add resistance or strength training at least 2 days per week to preserve muscle during weight loss
- Even modest increases in daily movement (walking, taking stairs) contribute meaningfully over time
However, weight loss is primarily driven by calorie balance. A calorie deficit of around 500 kcal per day typically results in approximately 0.5 kg weight loss per week. Fitness helps create this deficit, but dietary changes are equally important — often more so, as it is easier to reduce calorie intake than to burn off excess calories through exercise alone.
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 Options Alongside Your Fitness Programme
For many people, combining fitness with structured weight management UK support produces better results. This may include NHS weight loss schemes, behaviour change programmes, or prescription weight loss medication in appropriate cases.
- GLP-1 weight loss medications (such as Wegovy or Mounjaro) may help reduce appetite and support feeling fuller after smaller meals, working alongside your fitness routine
- These are prescription-only and require assessment by a GP or licensed prescriber
- Medication is never a substitute for fitness and diet — it is a tool to support your efforts
- Weight loss medication can improve medication nhs accessibility through specialist services or private online prescribing
Use our free BMI calculator above to check your current BMI and understand your starting point. If you meet eligibility criteria (BMI 30 or above, or 27+ with weight-related health conditions), discuss prescription options with your GP.
- 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 much exercise do I need for a weight loss fitness programme?
The NHS recommends 150 minutes of moderate-intensity aerobic activity per week plus resistance training at least twice weekly. However, weight loss is primarily driven by calorie deficit, not exercise volume alone. A sustainable approach combines regular fitness with dietary changes — aim for consistency rather than extreme intensity.
Can I lose weight through fitness alone without changing my diet?
Weight loss through exercise alone is very difficult. You would need to burn a very large calorie surplus through activity, which is time-consuming and unsustainable. Combining fitness with a reduced-calorie diet (typically 500 kcal deficit per day) produces much better results and is more achievable for most people.
Should I do cardio or weights for weight loss?
Both are valuable. Cardio burns calories during exercise. Weights build muscle, which increases your resting metabolic rate (the calories you burn at rest). A combination of both, alongside calorie reduction, is most effective. If choosing one, prioritise whichever you will do consistently.
Can prescription weight loss medication like Wegovy help with my fitness programme?
Yes, GLP-1 medications may help by reducing appetite and cravings, making it easier to maintain a calorie deficit while you exercise. However, they require a prescription and clinical assessment. Medication is not a shortcut — it is a tool to support your fitness and diet efforts. Results vary between individuals.
What should my target weight loss rate be?
The NHS recommends losing 0.5 to 1 kg per week for sustainable weight loss. This typically requires a calorie deficit of around 500 kcal per day. Faster loss risks muscle loss and is harder to maintain. Use our free progress tracker to log your weight over time and monitor your rate of 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.