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, you can lose weight without exercise—but it requires a structured approach focused on nutrition and, for some, prescription medication. Weight loss happens primarily through creating a calorie deficit, which is achievable through dietary changes alone. However, the NHS emphasises that combining dietary changes with physical activity produces the best long-term results for weight management in the UK. If exercise isn't possible due to injury, mobility issues, or other circumstances, other evidence-based options including prescription weight loss medications may help support your weight management journey.
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.
How Weight Loss Without Exercise Works
Weight loss fundamentally requires a calorie deficit—consuming fewer calories than your body uses. This can be achieved through diet alone, without exercise. The NHS recommends a deficit of around 500 calories per day to lose approximately 0.5 kg per week sustainably. To create this deficit without exercise, you need to reduce food intake, choose lower-calorie foods, and increase protein intake (which supports satiety). Using our free weight converter and BMI calculator can help you establish your baseline health metrics and set realistic targets. Some individuals find prescription weight loss medication helpful—options like GLP-1 injections (such as Wegovy or Mounjaro) may help reduce appetite and support weight management when used alongside a reduced-calorie diet. These are prescription-only and require clinical assessment from a GP or licensed prescriber.
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.
NHS Guidance and Weight Loss Medication Options
The NHS weight management pathway starts with tier 1 support—self-help tools, digital resources, and community programmes. Prescription weight loss medications are typically available through tier 3 specialist services, though private access via licensed online prescribers is also available. GLP-1 weight loss injections like Wegovy (semaglutide) are prescription-only and work by reducing appetite and helping you feel fuller after smaller meals. Clinical trials showed participants lost an average of 15% of body weight—though individual results vary significantly. Our GLP-1 weight loss calculator can help estimate potential weight loss at different medication doses. Any prescription weight loss treatment should be combined with dietary changes; medication supports but does not replace the need for reduced-calorie eating.
- 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 I lose weight by diet alone without any exercise?
Yes. Weight loss requires a calorie deficit, which can be created entirely through dietary changes. The NHS recommends reducing intake by around 500 calories daily for sustainable loss of approximately 0.5 kg per week. However, combining diet with some physical activity, even light activity like walking, produces better long-term results and supports muscle preservation.
What if I can't exercise due to injury or illness?
Diet remains effective for weight loss without exercise. Focus on whole foods, increase protein intake to maintain satiety, and track calories. If you've been unable to exercise long-term, discuss with your GP whether prescription weight loss medication (such as GLP-1 injections) might support your weight management alongside dietary changes.
How long does it take to lose weight through diet only?
At a sustainable rate of 0.5–1 kg per week (created by a 500–1000 calorie daily deficit), you might lose 2–4 kg per month through diet alone. Results vary based on starting weight, age, metabolism, and adherence. Use our free progress tracker to monitor your journey.
Are weight loss injections effective without exercise?
Yes. Clinical trials of GLP-1 medications like Wegovy showed average weight loss of 15% of body weight alongside a reduced-calorie diet—exercise was not required, though it was encouraged. These are prescription-only and must be prescribed by a licensed healthcare professional following assessment.
What's the best diet for weight loss without exercise?
Evidence supports Mediterranean diet, intermittent fasting, and low-carbohydrate approaches—all produce weight loss through calorie deficit. The best diet is one you can sustain. Focus on whole foods, adequate protein, plenty of vegetables, and consistent calorie intake. Your GP or a dietitian can provide personalised guidance for your situation.
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.