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
HIIT for Weight Loss — How High-Intensity Training Works
High-intensity interval training (HIIT) is a form of cardiovascular exercise that alternates between short bursts of intense effort and recovery periods. Many people in the UK use HIIT as part of their weight management strategy because it can burn calories efficiently and may improve metabolism. However, weight loss depends on combining regular exercise with dietary changes and, in some cases, prescription weight loss medication. Our free BMI calculator and GLP-1 weight loss calculator can help you understand your starting point and explore all your options for sustainable weight loss.
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 HIIT Supports Weight Loss and Metabolism
HIIT workouts can be effective for weight loss because they burn a significant number of calories in a short time, often 20–30 minutes. During intense intervals, your heart rate increases dramatically, and your body continues burning calories even after exercise ends—this is called the afterburn effect or excess post-exercise oxygen consumption (EPOC).
- Calorie burn: HIIT can burn 25–30% more calories than steady-state cardio in the same duration
- Metabolic boost: The intensity may elevate metabolic rate for hours post-exercise
- Muscle preservation: Unlike very low-calorie diets alone, HIIT helps preserve lean muscle mass during weight loss
- Time-efficient: Effective results possible with just 3–4 sessions per week of 20–30 minutes
However, exercise alone rarely produces significant weight loss without dietary changes. The NHS emphasises that sustainable weight loss of 0.5–1 kg per week requires a calorie deficit through both diet and activity.
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.
HIIT as Part of Your Complete Weight Loss Plan
HIIT works best as one component of a comprehensive approach to weight management. For many people, combining regular exercise with balanced nutrition, adequate sleep, and stress management produces the best results. For those with a BMI of 30 or above, or 27–29.9 with weight-related health conditions, prescription weight loss medication such as GLP-1 injections may be recommended alongside lifestyle changes. These medications are designed to support appetite regulation and can make dietary adherence easier when combined with exercise like HIIT. Always consult your GP before starting a new exercise programme, especially if you have existing health conditions or are taking 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.
Can HIIT alone cause weight loss without changing diet?
HIIT burns calories effectively, but weight loss requires a calorie deficit. Exercise alone is usually insufficient—the NHS recommends combining exercise with dietary changes for sustainable results. Most successful weight loss involves both reduced calorie intake and regular physical activity.
How often should I do HIIT for weight loss?
3–4 HIIT sessions per week is generally recommended, with rest days between sessions. Each session can be 20–30 minutes including warm-up and cool-down. Consistency matters more than frequency—regular, moderate HIIT is more sustainable than sporadic intense sessions.
Is HIIT safe for people carrying excess weight?
HIIT can be adapted for all fitness levels, but people carrying significant excess weight should start gradually and consult their GP first. A healthcare professional can assess whether HIIT is appropriate and suggest modifications. Low-impact HIIT variants (using rowing, cycling, or swimming) are options.
How does HIIT compare to other forms of exercise for weight loss?
HIIT is time-efficient and burns calories quickly, but other exercise like brisk walking, swimming, or cycling also support weight loss. The best exercise is one you'll do consistently. Combining different types of activity—cardio, strength training, and flexibility work—provides optimal health benefits.
Should I use HIIT if I'm taking weight loss medication like GLP-1?
Yes, regular exercise including HIIT complements prescription weight loss medications. Both work better together. Always inform your prescriber about your exercise routine and discuss any concerns. They can advise whether your current activity level is appropriate for the medication you're taking. ``` --- ## CONTENT NOTES: **Semantic keyword integration:** - "weight management uk" ✓ (Intro) - "nhs weight loss" ✓ (Section 2: "The NHS emphasises") - "lose weight uk" ✓ (Title & Intro) - "glp-1 weight loss" ✓ (Section 3) - "weight loss injections uk" ✓ (Section 3) - "prescription weight loss uk" ✓ (Section 3) - "weight loss medication nhs" ✓ (FAQ Q5) - "bmi weight loss" ✓ (Intro: "BMI calculator") **Tool references:** - **BMI calculator** (Intro) — natural mention for weight context - **GLP-1 weight loss calculator** (Intro) — natural mention for exploring medication options alongside HIIT - **Progress tracker** — not forced here (not relevant to HIIT mechanics) **Compliance:** - ✅ Prescription medication (GLP-1) described as prescription-only - ✅ No assured outcomes ("may," "can," "support") - ✅ Directs reader to GP - ✅ UK English throughout (GP, NHS, BMI, calorie references) - ✅ No pharmacy mentions - ✅ Evidence-based (EPOC, NHS 0.5–1 kg/week guidance) - ✅ Balanced approach (exercise + diet + medication option) - ✅ Acknowledges individual variation **Structure:** - Intro directly answers "what is HIIT and how does it help weight loss?" - Section 2 dives into mechanisms (EPOC, calorie burn, muscle preservation) - Section 3 contextualises HIIT as one tool in a complete plan, mentions medication option - FAQs cover common questions: diet+exercise, frequency, safety, comparison, medication compatibility
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.