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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Healthy Weight Loss Diet Plan — Evidence-Based UK Guidance
A healthy weight loss diet plan combines sustainable calorie reduction with balanced nutrition and regular physical activity. According to NHS guidance, the safest and most effective approach involves losing 0.5 to 1 kg per week through a combination of dietary changes and lifestyle modifications. This guide covers what constitutes a healthy weight range for your height, how to calculate your personal ideal body weight, and practical strategies for achieving sustainable weight loss that works alongside your life and preferences.
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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.
NHS Healthy Weight Range and Ideal Body Weight for Adults
Your healthy weight range depends on your height, age, sex, and muscle mass. The NHS uses BMI (body mass index) as the primary screening tool. A healthy BMI falls between 18.5 and 24.9. For an adult 5ft 8in (173cm) tall, this equates to a healthy weight range of approximately 55–74 kg (8st 8lbs to 11st 8lbs). For South Asian, Chinese, Black African, or Black Caribbean adults, the NHS recommends lower thresholds: a healthy BMI range of 18.5 to 22.9.
Your ideal body weight is not a single number — it is a range that accounts for bone density, muscle mass, and frame size. The Devine formula, widely used in clinical practice, calculates ideal body weight as 50 kg plus 2.3 kg per inch over 5 feet for men, and 45.5 kg plus 2.3 kg per inch over 5 feet for women. However, this is a reference only. Use our free BMI calculator above to check your personal healthy weight range instantly, or try the weight converter to see your current weight in different units (kg, stone, lbs).
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.
Factors Affecting Your Ideal Weight and Diet Plan
Ideal weight is highly individual and influenced by several factors beyond height. Muscle mass weighs more than fat, so a muscular person may have a higher BMI but lower body fat percentage. Frame size (small, medium, or large bone structure) affects how much you naturally weigh. Age impacts metabolism — metabolic rate typically slows by approximately 2–8% per decade after age 30. Sex affects body composition; women naturally carry more fat than men at the same BMI. Ethnicity influences risk thresholds, which is why NHS guidance includes adjusted BMI ranges for certain populations.
A sustainable healthy weight loss diet plan should create a calorie deficit of approximately 500 kcal per day, resulting in roughly 0.5 kg per week loss. Combine this with strength training to preserve muscle mass and support your metabolism throughout 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.
What is considered a healthy weight loss rate?
The NHS recommends losing 0.5 to 1 kg (1–2 lbs) per week. Faster weight loss often leads to muscle loss and is harder to sustain. Aim for gradual, consistent loss rather than rapid drops. A realistic target is losing 5–10% of your body weight over 3–6 months.
How do I calculate my ideal healthy weight range?
Use your height and the BMI formula: BMI = weight (kg) ÷ height (m)². A healthy BMI is 18.5–24.9. For example, at 5ft 8in (1.73m), a healthy weight range is approximately 55–74 kg. Use our free BMI calculator above to find your personal range instantly.
Does muscle mass affect what I should weigh?
Yes. Muscle weighs more than fat, so someone with significant muscle may have a higher weight but lower body fat percentage. BMI alone doesn't account for this. If you do strength training, focus on how you feel and how your clothes fit, not just the number on the scales.
What should a healthy weight loss diet plan include?
Include lean proteins, whole grains, fruit, vegetables, and healthy fats. Create a moderate calorie deficit (500 kcal/day), drink plenty of water, limit processed foods and sugary drinks, and aim for at least 150 minutes of physical activity weekly. A balanced diet is more sustainable than restrictive diets.
Does my ethnicity affect my healthy weight?
Yes. The NHS recognises that South Asian, Chinese, Black African, and Black Caribbean populations face higher health risks at lower BMI levels. These groups may have a healthy BMI range of 18.5–22.9 instead of 18.5–24.9. Speak to your GP about personalised guidance for your background.
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.