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
Can You Lose Weight Without Exercise?
Yes, weight loss without exercise is possible — but it requires a deliberate calorie deficit through dietary changes. The NHS confirms that weight management is fundamentally about energy balance: you lose weight when you consume fewer calories than you burn, regardless of activity level. However, exercise amplifies results and protects muscle mass during weight loss. For UK adults seeking additional support, prescription weight loss medication like GLP-1 injections can help manage appetite alongside dietary changes, though this requires clinical assessment and a prescription from a GP or licensed prescriber.
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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 Weight Loss Works Without Exercise
Weight loss happens through a calorie deficit — consuming fewer calories than your body uses each day. Without exercise, this deficit must come entirely from diet. The NHS recommends losing 0.5 to 1 kg per week, which typically requires a deficit of around 500 kcal daily. This can be achieved through: reducing portion sizes, choosing lower-calorie foods, cutting back on sugary drinks and snacks, and eating more protein and fibre (which keeps you fuller longer). The challenge is appetite management — without physical activity to tire your body, hunger signals remain strong. This is where dietary strategies matter most: drinking water before meals, eating slowly, avoiding highly processed foods, and planning meals ahead all help. For some UK adults, prescription weight loss medication like GLP-1 injections (Wegovy or Mounjaro) may be appropriate following clinical assessment. These medications help reduce appetite and food cravings, making the calorie deficit easier to maintain alongside dietary 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.
Weight Loss Medication as a Support Tool
Prescription weight loss medications can support weight management without exercise by helping control hunger and cravings. Wegovy (semaglutide) is a GLP-1 injection licensed in the UK for weight management in adults with a BMI of 30 or above, or 27–29.9 with weight-related health conditions like type 2 diabetes or high blood pressure. Clinical trials showed participants lost an average of around 15% of their body weight — though individual results vary significantly. Mounjaro (tirzepatide) is another option using dual GIP and GLP-1 mechanisms. Both are prescription-only and require a clinical assessment before being prescribed. They work alongside dietary changes, not instead of them. Your GP or a licensed prescriber can assess whether prescription weight loss medication is suitable for you. Use our free GLP-1 weight loss calculator to see projected outcomes at different doses, and our BMI calculator to check your starting point.
- 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.
Can you really lose weight with diet alone, no exercise?
Yes. Weight loss fundamentally requires a calorie deficit, which can be achieved through diet alone. The NHS confirms this. However, exercise provides additional benefits: it preserves muscle mass, improves fitness, and supports long-term weight maintenance. Without exercise, ensure your diet includes adequate protein and you're losing weight gradually (0.5–1 kg/week) to minimise muscle loss.
How much weight can you lose without exercising?
This depends on your calorie deficit. A deficit of 500 kcal daily typically results in losing approximately 0.5 kg per week. Larger deficits can produce faster loss but aren't sustainable long-term and increase health risks. Prescription weight loss medication may help create a sustainable deficit by reducing appetite, though individual results vary.
What's the best diet for weight loss without exercise?
Any diet creating a consistent calorie deficit works — low carbohydrate, Mediterranean, intermittent fasting, or simple calorie counting. The best diet is one you can stick to. Focus on: whole foods, adequate protein (helps you feel fuller), fibre-rich vegetables, and avoiding liquid calories. Consistency matters more than perfection.
Does prescription weight loss medication work without exercise?
Prescription medications like Wegovy (semaglutide) and Mounjaro (tirzepatide) are designed to work alongside dietary changes. Clinical trials showed average weight loss of 15–21% — but these trials also included reduced-calorie diets. Medication helps manage appetite and cravings, making a calorie deficit easier to maintain. Results vary individually.
Is weight loss without exercise safe?
Yes, if done gradually (0.5–1 kg/week) through a modest calorie deficit. Very gradual weight management without medical supervision can cause muscle loss, nutritional deficiencies, and gallstones. Consult your GP before starting any significant dietary change or weight loss medication. They can advise what's safe for your individual health.
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.