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
Can Drinking Shakes Help You Lose Weight?
Yes, drinking protein and meal replacement shakes can support weight loss when used as part of a structured plan. In the UK, shakes are often used alongside lifestyle changes and, in some cases, prescription weight loss medication to create the calorie deficit needed for sustainable weight management. However, shakes alone won't lead to lasting results — they work best combined with a balanced diet, increased physical activity, and professional support. Your GP can advise whether meal replacement shakes are appropriate for your individual health needs and weight loss goals.
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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 Shakes Support Weight Loss
Protein and meal replacement shakes support weight loss in several evidence-based ways. They provide controlled calorie intake — a standard meal replacement shake contains 150–250 kcal, compared to 600–800 kcal for a typical meal, making it easier to maintain the calorie deficit needed for weight loss. Shakes are also convenient and portion-controlled, removing guesswork from meal planning. Many contain added protein, which increases satiety (feeling fuller for longer) and helps preserve muscle mass during weight loss. Some studies suggest protein intake of 1.6–2.2g per kg body weight supports better muscle retention than lower-protein diets.
- Protein shakes (whey, plant-based) — best used as a snack or meal supplement, not sole nutrition
- Meal replacement shakes — designed to replace one or two meals daily with complete nutrition
- Low-sugar formulations — important for stable blood sugar and sustained energy
However, shakes must be combined with healthy eating and activity for lasting results. The NHS recommends losing weight at a rate of 0.5–1 kg per week through a combination of dietary changes and increased physical activity. Try our free BMI calculator above to check your current weight category, and use our weight converter if you'd like to see your weight in different units.
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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.
Shakes Alongside Weight Loss Medication
In the UK, prescription weight loss medications like GLP-1 receptor agonists (Mounjaro and Wegovy) are increasingly used alongside meal replacement strategies. These medications help reduce appetite and food cravings, making it easier to stick to a lower-calorie intake that may include protein shakes. Evidence from clinical trials shows that Wegovy users achieved an average weight loss of approximately 15% of body weight when combined with lifestyle changes over 68 weeks — a structured approach that often includes meal planning and controlled nutrition.
If you're considering prescription weight loss treatment, our GLP-1 weight loss calculator can help you understand potential outcomes at different doses. Speak to your GP about whether prescription medication, combined with shakes and lifestyle changes, is right for you. Sustainable weight management in the UK typically involves a personalised approach combining nutrition, activity, professional support, and sometimes 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.
Are meal replacement shakes effective for weight loss?
Yes, when used as part of a structured plan. Studies show that meal replacement shakes can support weight loss by reducing overall calorie intake and increasing satiety. However, shakes alone are not effective — they must be combined with a balanced diet, increased physical activity, and lifestyle changes for lasting results.
How many shakes per day should I drink for weight loss?
Most UK guidance recommends replacing one or two meals per day with a shake, not all three meals. A typical approach is breakfast or lunch as a meal replacement shake (150–250 kcal each) with two balanced whole-food meals. Always consult your GP before starting any structured meal replacement plan, especially if you have medical conditions.
What's the difference between protein shakes and meal replacement shakes?
Protein shakes (typically 20–30g protein, 120–180 kcal) are supplements to existing meals. Meal replacement shakes (200–300 kcal, with carbs, fats, protein, and vitamins) are designed to replace a complete meal. Both can support weight loss, but meal replacements offer complete nutrition if used as directed.
Can shakes help me lose weight without exercise?
Shakes can support weight loss on their own through calorie reduction, but the NHS recommends combining dietary changes with increased physical activity for best results and overall health benefits. Even modest activity — 30 minutes of brisk walking most days — significantly improves outcomes.
Do shakes work better than regular food for weight loss?
Shakes and whole food can both support weight loss if they fit into a calorie deficit. Shakes are convenient and portion-controlled, but whole foods provide more nutrients and natural satiety. A balanced approach using both, alongside your GP's advice, typically works best for sustainable weight loss in the UK.
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.