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
High Intensity Interval Training Workouts for Weight Loss
High intensity interval training (HIIT) is a time-efficient exercise approach that alternates short bursts of intense activity with recovery periods. Evidence suggests HIIT can support weight management by boosting calorie burn and metabolic rate during and after exercise. However, sustainable weight loss requires combining physical activity with dietary changes and lifestyle improvements. Whether you're starting your fitness journey or looking to enhance your current routine, HIIT may complement a broader weight loss strategy. Use our free BMI calculator to assess your current weight status, and our GLP-1 weight loss calculator can help project potential outcomes when combining exercise with other weight management approaches.
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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 HIIT Supports Weight Loss and Metabolism
HIIT works by creating an "afterburn" effect, where your body continues burning calories at an elevated rate for hours after exercise ends. Short, intense bursts of effort push your cardiovascular system and muscles harder, increasing oxygen consumption and metabolic demand. Unlike steady-state cardio, HIIT typically involves 20–30 seconds of maximum effort followed by rest or low-intensity recovery periods, repeated for 15–30 minutes total.
- Studies show HIIT may burn more calories per minute than traditional aerobic exercise
- Interval training can improve insulin sensitivity, supporting better blood sugar control
- HIIT preserves muscle mass better than low-intensity cardio during weight loss
- Sessions are time-efficient — effective workouts can be completed in 20–30 minutes
However, HIIT is demanding and requires good fitness baseline or proper progression to avoid injury. Results vary based on current fitness level, diet quality, sleep, and consistency. When combined with a calorie deficit and strength training, HIIT can be a powerful tool for weight management.
Clinically BackedWeight Loss
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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.
HIIT and Weight Loss Medications — A Practical Approach
Exercise and prescription weight loss medications work through different mechanisms. Medications like GLP-1 injections used within NHS weight loss programmes or prescribed privately help regulate appetite and food intake, while HIIT creates a calorie deficit through increased energy expenditure. Together, they can complement each other — medication may reduce hunger, making it easier to maintain the dietary discipline required for weight loss, whilst exercise improves cardiovascular health and preserves muscle during weight loss.
For best results with any weight loss approach, focus on consistency over intensity. Aim for 150 minutes of moderate activity or 75 minutes of vigorous activity weekly, alongside 2–3 strength sessions. Track your progress using our free progress tracker, and consult your GP before starting any new exercise programme, especially if you have existing health conditions or are taking weight loss medication.
- 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.
Is HIIT better than steady cardio for weight loss?
Both can support weight loss — HIIT is more time-efficient and may burn more calories per minute, while steady cardio is easier to sustain and less demanding on joints. Choose based on your fitness level and preferences. Consistency matters more than the type of cardio chosen.
How often should I do HIIT workouts for weight loss?
Most evidence suggests 2–3 HIIT sessions per week, with rest days between for recovery. More frequent high-intensity work increases injury risk. Combine with strength training and moderate activity for balanced results.
Can HIIT replace a healthy diet for weight loss?
No. Weight loss requires a calorie deficit, which is primarily created through diet. HIIT supports this by increasing energy expenditure, but without dietary changes, weight loss results will be minimal. Exercise and nutrition work together.
Is HIIT safe for people starting weight loss?
HIIT is demanding and best suited to people with baseline fitness. Start with moderate activity, build strength and aerobic fitness first, then progress to HIIT. Always consult your GP before beginning a new exercise programme.
What's the best time to do HIIT — morning or evening?
The best time is when you'll do it consistently. Morning HIIT may boost metabolism throughout the day, whilst evening sessions suit some schedules. Consistency and frequency matter more than timing.
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.