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
Should You Exercise Before or After Eating for Weight Loss?
The timing of exercise around meals is less important than consistency and overall calorie balance for weight loss. Whether you exercise before or after eating depends on your personal comfort, fitness level, and health goals. Both approaches can support effective weight management UK when combined with a balanced diet and sustainable habits. Your GP or a healthcare professional can provide personalised guidance based on your individual circumstances and any weight-related health conditions you may have.
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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.
Exercise Timing: Before vs After Eating
Exercising on an empty stomach (before eating) may suit those who prefer fasted cardio or morning workouts. Some evidence suggests fasted exercise might increase fat utilisation, though weight loss ultimately depends on total calorie deficit. However, exercising without fuel can leave you feeling fatigued or dizzy, and may reduce workout intensity.
Exercising after eating provides energy from recent food intake, often enabling more intense or longer workouts. This typically supports better performance, especially for strength training or endurance exercise. Eating 1–2 hours before exercise allows digestion time; eating 30 minutes before suits lighter snacks like fruit or yoghurt.
- Fasted exercise: good for morning routines, may aid fat oxidation but may reduce intensity
- Fed exercise: better energy, improved performance, supports longer or harder workouts
- Individual factors: metabolism, fitness level, and personal preference all matter
The most effective approach is whichever you can sustain consistently. For prescription weight loss medication (such as GLP-1 weight loss options), exercise timing becomes secondary to the primary goal of building sustainable habits.
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.
Nutrition and Meal Timing for Weight Loss
For weight loss, meal composition matters more than timing relative to exercise. Eating balanced meals with adequate protein, fibre, and whole grains supports satiety and recovery. NHS weight loss guidance emphasises a consistent calorie deficit of around 500 kcal per day, achieved through diet and activity combined, typically resulting in 0.5–1 kg loss per week.
If you're considering prescription weight loss medication as part of your weight management UK plan, our free GLP-1 weight loss calculator can help you explore potential outcomes. Track your progress over time using our progress tracker, and use our BMI calculator to monitor how exercise and dietary changes affect your health metrics.
- Eat 1–2 hours before intense exercise for optimal digestion
- Include protein and carbohydrates for energy and recovery
- Stay hydrated before, during, and after activity
- 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.
Should I exercise before breakfast for weight loss?
There's no strong evidence that fasted morning exercise burns more fat overall. Total calorie balance matters most. If you prefer exercising before breakfast, ensure you eat a balanced meal afterwards and maintain overall calorie deficit. Listen to your body — some people feel stronger after eating a light snack first.
Is it better to exercise 30 minutes after eating or longer?
A gap of 1–2 hours after a full meal allows comfortable digestion, especially before intense exercise. Light snacks (banana, yoghurt) can be eaten 30 minutes before activity. Individual digestion varies, so experiment to find what feels best for your energy levels and comfort during workouts.
Can exercise timing affect my BMI or weight loss results?
Exercise timing has minimal impact on BMI or weight loss compared to overall calorie deficit and consistency. Calculate your current BMI using our free BMI calculator to establish your baseline. Focus on exercising regularly and maintaining healthy nutrition — these matter far more than whether you eat before or after.
What if I'm taking weight loss medication — does exercise timing change?
Prescription weight loss medication like GLP-1 injections works alongside exercise and dietary changes, not instead of them. Exercise timing remains a personal preference. Your prescriber may advise avoiding very intense exercise if you experience nausea early in treatment, but this is temporary.
How does NHS weight loss guidance recommend combining meals and exercise?
NHS weight loss guidance focuses on achieving a calorie deficit through balanced nutrition and regular physical activity, without strict rules on timing. Aim for 150 minutes moderate activity weekly, plus strength training twice weekly. Eat regular meals to fuel activity and prevent overeating later.
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.