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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Macro Percentages For Weight Loss: What Works
Macro percentages—the proportion of protein, carbohydrates, and fat in your diet—play an important role in sustainable weight loss. There's no single "perfect" ratio that works for everyone, but research-backed guidelines can help you find an approach that supports your goals. The NHS recommends balancing macronutrients alongside a calorie deficit, which is essential for losing weight at a healthy rate of 0.5–1 kg per week. This guide explains macro ratios, how they support weight loss, and how to calculate your own targets.
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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.
Common Macro Ratios For Weight Loss
Standard balanced approach: 40% carbohydrates, 30% protein, 30% fat. This is often recommended by the NHS for general weight management because it balances energy, fullness, and nutrient density.
Higher protein approach: 35% carbohydrates, 35% protein, 30% fat. Increasing protein helps preserve muscle mass during weight loss and supports satiety—meaning you feel fuller for longer. This is especially useful when combined with strength training.
Lower carbohydrate approach: 25% carbohydrates, 35% protein, 40% fat. Some people find lower-carb eating easier to follow, though long-term adherence matters more than the specific ratio. This approach may help reduce cravings for some individuals.
Research shows that adherence to your chosen approach is more important than the exact macro split. Calculate your personalised targets using your daily calorie needs—for example, if you're eating 2,000 kcal daily, 30% protein equals 150g.
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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, Satiety, And Weight Loss
Protein is especially important during weight loss because it helps preserve lean muscle mass and increases satiety—helping you feel satisfied on fewer calories. Aim for at least 1.2–1.6g of protein per kg of body weight daily when losing weight, particularly if you're exercising.
Good UK protein sources include chicken, fish, eggs, Greek yoghurt, lentils, beans, and tofu. Using the free BMI calculator on this page helps you understand your current weight context, and tracking your macros alongside a calorie deficit makes sustainable weight management much easier. Your GP can also refer you to NHS weight management services for personalised dietary guidance if needed.
- 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.
What are macronutrients and why do they matter for weight loss?
Macronutrients—protein, carbohydrates, and fat—are the three main nutrients your body needs for energy and function. The balance of these affects hunger, energy levels, and how much muscle you preserve during weight loss. Hitting your macro targets alongside a calorie deficit supports sustainable, healthy weight loss.
Is a high-protein diet better for weight loss?
Higher protein intake (around 30–35% of calories) can support weight loss by increasing satiety and helping preserve muscle mass. However, research shows that adherence to your chosen approach matters more than the exact percentage. Choose a ratio you can maintain long-term.
Can macro percentages help with weight loss without calorie counting?
Macro percentages work best alongside calorie awareness. You can focus on hitting protein targets and whole foods, which naturally supports a calorie deficit, but tracking your overall energy intake remains important for consistent results.
Should I adjust my macros if I'm taking weight loss medication like Mounjaro or Wegovy?
Yes. Weight loss injections like Mounjaro (tirzepatide) and Wegovy (semaglutide) often reduce appetite, so your calorie needs may decrease. Work with your prescriber or a nutritionist to adjust your macro targets accordingly and ensure adequate protein intake during weight loss.
How do I calculate my personal macro percentages?
First, calculate your daily calorie needs (your GP or a nutritionist can help). Then apply your chosen percentages—for example, 40% carbs at 2,000 kcal = 800 kcal ÷ 4 kcal per gram = 200g carbs daily. Use our free progress tracker to monitor your intake and results over time.
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.