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
Best Fitness Plan For Weight Loss
The best fitness plan for weight loss combines regular physical activity with a reduced-calorie diet and, where appropriate, prescription weight loss medication. In the UK, the NHS recommends losing weight at a sustainable rate of 0.5 to 1 kg per week through a combination of exercise, dietary changes, and behavioural support. Your GP can help you create a personalised plan based on your BMI, health conditions, and fitness level. Use our free BMI calculator to understand your starting point, then build a structured fitness and nutrition plan around evidence-based guidance.
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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.
Why Fitness Alone Isn't Enough for Weight Loss
While exercise is essential for overall health, fitness alone typically isn't sufficient for significant weight loss. Research shows that weight loss depends primarily on creating a calorie deficit through diet — approximately clinically studied weight loss comes from nutrition, with exercise contributing to the remaining 20%. This doesn't mean fitness isn't important; regular physical activity supports metabolic health, preserves muscle mass during weight loss, improves cardiovascular fitness, and enhances mental wellbeing. For sustainable weight management in the UK, the NHS recommends combining at least 150 minutes of moderate-intensity aerobic activity per week with strength training twice weekly. Adults with a BMI of 30 or above, or 27 or above with weight-related health conditions, may also be eligible for prescription weight loss medication through their GP or NHS specialist services. Prescription medications like Mounjaro or Wegovy work alongside fitness and diet, not instead of them — clinical trials showed these GLP-1 medications helped participants lose an average of 15–21% of body weight when combined with lifestyle changes.
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.
Building Your Personal Weight Loss Fitness Plan
Start by calculating your daily calorie needs using your current weight and activity level — a deficit of 500 kcal per day typically results in approximately 0.5 kg weight loss per week. Combine this with three types of exercise: aerobic activity (brisk walking, cycling, swimming), strength training (weights or bodyweight exercises), and flexibility work (yoga, stretching). Track your progress using our free progress tracker to monitor weight, fitness improvements, and motivation over time. If you're struggling to lose weight through diet and exercise alone after 12 weeks, speak to your GP about additional support, including referral to NHS tier 3 specialist weight management services. These services may offer behaviour change programmes, low-calorie diet support, or assessment for prescription weight loss medication. Remember that weight management in the UK is a personalised journey — what works for others may need adjusting for your individual circumstances, preferences, and health conditions.
- 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 weight loss?
The NHS recommends at least 150 minutes of moderate-intensity aerobic activity per week (such as brisk walking or cycling), plus strength training twice weekly. However, exercise works best combined with a calorie-deficit diet — weight loss depends primarily on nutrition. Use our GLP-1 weight loss calculator to explore how medication might support your fitness and diet efforts.
Can I lose weight through fitness alone without changing my diet?
Unlikely. Weight loss requires a calorie deficit, which is mainly achieved through diet — exercise alone rarely creates a large enough deficit. However, fitness supports metabolism, muscle retention, and overall health during weight loss, so combining both is ideal for sustainable results.
What's the best type of exercise for weight loss?
A combination approach works best: moderate-intensity aerobic activity (walking, running, cycling), strength training (weights or bodyweight), and flexibility work. Consistency matters more than intensity — choose activities you enjoy so you'll stick with them long-term.
How long before I see weight loss results from exercise?
Most people notice health improvements within 2–4 weeks, but visible weight loss typically takes 4–8 weeks depending on diet quality and consistency. The NHS recommends losing 0.5–1 kg per week for sustainable, healthy weight loss without rapid muscle loss.
Should I consider weight loss medication alongside fitness?
If you have a BMI of 30 or above (or 27+ with weight-related health conditions) and diet and exercise haven't worked after 12 weeks, speak to your GP. Prescription weight loss medications like Mounjaro or Wegovy may be eligible through NHS services or private prescribing, always used alongside fitness and diet 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.