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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Weights vs Cardio for Weight Loss — Which Works Better?
When it comes to weight loss, both weights and cardio have important roles to play — but they work differently. The truth is that diet is the foundation of weight loss, but exercise type matters for how your body changes and how sustainable your results are. This guide explains the science behind each, helps you understand which suits your goals, and shows why combining both is often the most effective approach for sustainable weight management in the UK.
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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 Weights and Cardio Compare for Weight Loss
Cardio (running, cycling, swimming) burns calories quickly during the session. A 30-minute moderate cardio session might burn 200–400 calories depending on intensity and body weight. This creates an immediate calorie deficit, which is why cardio is often the first choice for gradual weight management.
Weights (resistance training) burns fewer calories during the session (typically 150–300 calories in 30 minutes) but builds muscle tissue. Muscle tissue is metabolically active — it burns calories at rest. Over time, more muscle means a higher resting metabolic rate, supporting long-term weight management. Weights also prevent muscle loss during weight loss, which cardio alone cannot do.
- Cardio: faster calorie burn, good for immediate deficit
- Weights: builds muscle, supports long-term metabolism, prevents muscle loss
- Combined: maximises fat loss while preserving muscle
Research shows that combining both approaches produces better body composition changes than either alone. Using our free BMI calculator above can help you track your current weight status and set realistic goals for either approach.
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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.
The Role of Diet in Weight Loss Success
Whether you choose weights, cardio, or both, diet remains the critical factor. The NHS recommends a calorie deficit of around 500 kcal per day for sustainable loss of approximately 0.5 to 1 kg per week. You cannot out-exercise a poor diet — a 30-minute cardio session burns roughly 300 calories, but a single takeaway meal can contain 1,200+ calories.
Exercise supports weight loss by creating additional deficit, preserving muscle, and improving cardiovascular health. For weight management in the UK, the most effective approach combines regular physical activity with sustainable dietary changes. Track your progress using our free progress tracker to see how lifestyle changes affect your weight over time. If you're struggling with weight loss through exercise and diet alone, discuss prescription weight loss medication 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.
Does cardio burn more calories than weights?
Yes, cardio typically burns more calories per session. A 30-minute run might burn 300–400 calories, while 30 minutes of weights burns 150–300 calories. However, weights build muscle which increases your resting metabolic rate over time, supporting long-term weight management.
Will weights make me bulky if I'm trying to lose weight?
No. Building significant muscle bulk requires specific training, nutrition surplus (eating more calories), and often takes years. During weight loss with a calorie deficit, weights help preserve existing muscle and prevent the metabolic slowdown that cardio alone can cause.
What's the best exercise for weight loss — weights or cardio?
Combining both is most effective. Cardio creates immediate calorie deficit, while weights preserve muscle and support metabolism. The NHS recommends 150 minutes of moderate activity plus strength training twice weekly for optimal health and sustainable weight loss.
Can I lose weight with just weights and no cardio?
Yes, weight loss depends primarily on calorie deficit, not exercise type. However, cardio offers cardiovascular benefits and can create deficit more quickly. A balanced approach combining both, alongside diet changes, is recommended for health and body composition.
Does exercise alone cause weight loss without changing diet?
Not typically. Most weight loss comes from dietary changes. Exercise alone rarely creates sufficient deficit — for example, 300 calories burned in cardio is easily negated by an extra snack. The NHS recommends combining diet and exercise for sustainable weight loss and weight management in the UK.
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.