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
Free Weight Loss Diet Plan for UK Adults
A free weight loss diet plan doesn't need to be complicated or expensive. Whether you're looking for weight management through NHS resources or exploring prescription weight loss options, sustainable weight loss combines a reduced-calorie diet with increased physical activity. The NHS recommends losing weight at a rate of 0.5 to 1 kg per week for lasting results. This guide covers evidence-based approaches to losing weight, from dietary strategies to understanding when prescription medications might be appropriate for your situation.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
Evidence-Based Dietary Approaches to Weight Loss
A successful weight loss diet is built on creating a calorie deficit — typically around 500 kcal per day results in approximately 0.5 kg weight loss per week. The NHS Weight Loss Plan offers free resources including meal plans and activity trackers for UK adults. Several dietary approaches show good evidence:
- Mediterranean diet: Emphasises vegetables, olive oil, fish, and whole grains — excellent for cardiovascular health alongside weight loss
- Low-calorie balanced diet: 1,200–1,500 kcal daily with balanced macronutrients (proteins, carbohydrates, fats)
- Intermittent fasting: 16:8 or 5:2 patterns — evidence supports modest weight loss comparable to standard calorie restriction
- Protein-rich approach: Higher protein intake supports satiety and preserves muscle mass during weight loss
The most effective diet is one you can sustain long-term. Try our free weight converter and BMI calculator to track where you are now and set realistic targets aligned with NHS healthy weight guidance.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
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.
When to Consider Professional Support and Prescription Options
If diet and lifestyle changes alone haven't achieved results, your GP can discuss prescription weight loss options. GLP-1 weight loss injections like Wegovy (semaglutide) and Mounjaro (tirzepatide) are now available in the UK for adults with a BMI of 30 or above, or 27–29.9 with weight-related health conditions. These prescription medications work alongside diet and exercise — not instead of them. Our GLP-1 weight loss calculator can help you explore potential outcomes at different doses. NHS access is through tier 3 specialist weight management services, though waiting lists vary by region. Private prescribing is also available following an online clinical assessment.
- 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 weight can I realistically lose with a free diet plan?
A sustainable rate is 0.5–1 kg per week following a calorie-deficit diet. Over 12 weeks, this could mean 6–12 kg weight loss. Results depend on your starting point, consistency, and adherence. Even 5–clinically studied weight loss brings meaningful health benefits like improved blood pressure and blood sugar control.
Is the NHS Weight Loss Plan really free?
Yes. The NHS Weight Loss Plan is completely free and available online. It includes a 12-week diet and activity programme with meal ideas, shopping lists, and activity trackers. Your GP can also refer you to local community weight management services, many of which are free or low-cost.
What's the difference between weight loss diet plans and prescription weight loss injections?
Diet plans focus on calorie reduction and lifestyle change. Prescription injections like Wegovy and Mounjaro reduce appetite and support feeling fuller — but they're only prescribed after clinical assessment and work best alongside diet and exercise. Injections are suitable for specific BMI thresholds and health conditions.
Can I use our free tools to track my diet plan progress?
Yes. Use our free weight converter to log weight in stone, lbs, or kg. Use our BMI calculator to track BMI changes. Our progress tracker lets you log weekly weight and see trends over time. These tools help you stay motivated and monitor whether you're on track.
Do I need to cut out foods completely on a weight loss diet?
No. Sustainable weight loss doesn't require cutting out foods. Focus on portion control, choosing nutrient-dense foods most of the time, and allowing flexibility. Overly restrictive diets are hard to maintain and often lead to rebound weight gain. Balance, moderation, and consistency matter more than perfection.
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.