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
What Does Protein Do For Weight Loss?
Protein plays a crucial role in supporting weight loss by helping you feel fuller for longer, preserving muscle mass during weight loss, and boosting your metabolism. Whether you're managing your weight through lifestyle changes, prescription medication, or a combination of both, adequate protein intake is a key part of a successful weight management strategy in the UK. Understanding protein's role helps you make informed decisions about your diet and weight health.
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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 Protein Supports Weight Loss
Protein helps with weight loss in several important ways. First, it increases satiety — meaning you feel satisfied after eating smaller portions, which naturally reduces your overall calorie intake. Second, protein has a higher thermic effect than carbohydrates or fats, meaning your body burns more calories digesting protein itself. Third, during weight loss, adequate protein preserves lean muscle mass, which is essential because muscle burns more calories at rest than fat.
- Satiety: Protein keeps you feeling full longer, reducing hunger between meals
- Metabolic boost: Your body uses more energy processing protein than other nutrients
- Muscle preservation: Prevents loss of muscle mass during calorie deficit, maintaining your metabolism
- Blood sugar stability: Protein slows digestion, preventing blood sugar spikes and energy crashes
For those using prescription weight loss medication like GLP-1 injections for weight management in the UK, adequate protein becomes even more important — these medications may reduce appetite, so ensuring your diet includes sufficient protein helps maintain muscle and supports sustainable weight 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.
Protein Intake and Weight Loss Results
The NHS and UK health guidelines recommend higher protein intake during weight loss — typically 1.2 to 1.6 grams of protein per kilogram of body weight daily, compared to 0.8g/kg for weight maintenance. For example, a person weighing 80kg might aim for 96–128g of protein daily during weight loss.
- Lean meats: Chicken breast, turkey, lean beef — excellent protein sources
- Fish: Salmon, cod, mackerel — high protein and heart-healthy omega-3 fats
- Eggs: Complete protein with all essential amino acids
- Dairy: Greek yoghurt, cottage cheese, milk — high-protein options
- Plant-based: Lentils, chickpeas, tofu, nuts — protein for vegetarian and vegan diets
Track your progress using our free progress tracker to monitor both weight changes and dietary consistency. Combined with regular physical activity, adequate protein helps achieve sustained, healthy weight loss at a rate of 0.5–1kg per week as recommended by the NHS.
- 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.
How much protein do I need daily for weight loss?
UK health guidelines suggest 1.2–1.6g of protein per kilogram of body weight during weight loss. For an 80kg person, that's approximately 96–128g daily. Your GP or a registered dietitian can provide personalised guidance based on your individual circumstances.
Does protein alone cause weight loss?
No. Weight loss requires a calorie deficit — eating fewer calories than your body burns. Protein supports this by increasing satiety and preserving muscle, but it works best alongside a balanced diet and physical activity.
Can I get enough protein on a vegetarian or vegan diet?
Yes. Plant-based sources like lentils, chickpeas, tofu, tempeh, nuts, seeds, and beans all contain good protein. Combining different plant proteins ensures you get all essential amino acids.
Is protein important if I'm taking Mounjaro or Wegovy?
Yes, especially important. GLP-1 medications reduce appetite, which can make it harder to eat enough food overall. Focusing on protein-rich meals ensures your body receives adequate nutrition while losing weight, protecting muscle mass.
How does protein affect BMI and weight loss outcomes?
Protein doesn't directly change your BMI calculation, but it supports the weight loss that improves BMI. By preserving muscle mass during weight loss, you achieve better body composition — lower body fat percentage even if the scale shows modest changes. Use our free BMI calculator to track your progress.
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.