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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How Does Protein Help With Weight Loss?
Protein plays a key role in supporting weight loss by helping you feel fuller for longer, preserving muscle mass during weight loss, and increasing the energy your body uses to digest food. Whether you're managing your weight through diet and exercise alone or using prescription weight loss medication like Mounjaro or Wegovy, adequate protein intake can enhance your results. This guide explains the science behind protein and weight management in the UK context, helping you make informed decisions about your nutrition and nhs weight loss journey.
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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 reduces hunger and cravings. Protein is more satiating than carbohydrates or fats, meaning it keeps you feeling satisfied after eating. This helps reduce overall calorie intake without requiring constant willpower. Studies show protein increases levels of hormones like peptide YY and GLP-1 (the same hormone targeted by weight loss injections), which signal fullness to your brain.
Protein preserves muscle during weight loss. When you create a calorie deficit for weight management in the UK, your body can break down both fat and muscle. Adequate protein intake (approximately 1.6–2.2g per kg of body weight) helps protect lean muscle mass, ensuring more of the weight you lose is fat rather than muscle. This matters because muscle burns more calories at rest.
Protein has a higher thermic effect. Your body uses more energy digesting protein than carbs or fats — about 20–30% of protein calories are used during digestion, compared to 5–10% for carbs and 0–3% for fats. This means eating protein slightly boosts your metabolic rate.
- Lean meat, fish, eggs, and dairy are excellent protein sources
- Plant-based options include legumes, tofu, nuts, and seeds
- Aim for protein with every meal for consistent appetite control
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.
Protein and Prescription Weight Loss Medication
If you're using prescription weight loss medication like Mounjaro or Wegovy for weight management, protein becomes even more important. These GLP-1 medications reduce appetite naturally, but they also slow gastric emptying — meaning food stays in your stomach longer. Protein is easier to digest in this slower state and helps prevent nausea, a common side effect of these medications. Additionally, protein supports the muscle-sparing benefits you want during weight loss on medication.
A balanced approach combining adequate protein intake with reduced overall calories and increased physical activity tends to produce the best results. Try our free GLP-1 weight loss calculator to estimate potential outcomes with prescription medication, or use our BMI calculator to establish your current health baseline. Track your progress with our free progress tracker to see how dietary adjustments affect your weight loss journey.
- 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?
The NHS and most evidence suggests 1.6–2.2g of protein per kilogram of body weight daily during weight loss. For example, an 80kg person would aim for 128–176g daily. This is higher than the standard recommendation because it helps preserve muscle during calorie deficit. Your GP or a registered dietitian can provide personalised guidance based on your health status and activity level.
Does protein help with weight loss on its own?
No. Protein supports weight loss by reducing hunger and preserving muscle, but weight loss ultimately requires a calorie deficit. You must consume fewer calories than you burn. Protein helps you maintain that deficit more comfortably by keeping you fuller, but without an overall calorie reduction, weight loss won't occur.
What are the best protein sources for UK weight loss?
Lean meats (chicken, turkey, lean beef), fish (especially oily fish like salmon), eggs, Greek yoghurt, cottage cheese, legumes (lentils, beans), and nuts are all excellent. Plant-based and animal-based proteins are equally effective for weight loss — choose based on your preferences and dietary requirements. Vary your sources to get a range of nutrients.
Does protein help if I'm taking Wegovy or Mounjaro?
Yes. These prescription weight loss medications reduce appetite naturally, but adequate protein helps prevent nausea (a common side effect), supports muscle preservation during weight loss, and maintains satiety. Combine protein-rich meals with your medication, reduced calories, and increased activity for optimal results. Consult your prescriber about your specific nutrition plan.
Can too much protein be harmful?
For most healthy adults, high protein intake (up to 2.2g per kg body weight) is safe. However, people with kidney disease should consult their GP before increasing protein significantly, as damaged kidneys may struggle to process excess protein. Ensure you drink adequate water and maintain good overall nutrition alongside higher protein intake.
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.