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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1200 Calorie Meal Plan For Weight Loss — UK Guidance
A 1200 calorie meal plan is a low-calorie diet approach that some people use for weight loss. However, 1200 calories is considered a low calorie diet (LCD) and should only be followed under medical supervision. The NHS recommends safer, sustainable weight loss of 0.5 to 1 kg per week. If you're struggling with weight management in the UK, there are now prescription options available alongside dietary changes. This guide explains meal planning, NHS guidance, and when to discuss professional support with your GP.
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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.
Prescription Weight Loss Options Available in the UK
For eligible adults in the UK, prescription weight loss medications may be an option alongside dietary changes. Three UK-licensed medications are available:
- Mounjaro (tirzepatide) — a once-weekly injection that works as a dual GIP and GLP-1 receptor agonist, helping reduce appetite and support feeling fuller after meals. Clinical trials showed average weight loss of 15–21% of body weight when combined with lifestyle changes.
- Wegovy (semaglutide) — a once-weekly GLP-1 injection. Evidence suggests average weight loss of around 15% body weight in clinical trials alongside reduced-calorie diet and physical activity.
- Saxenda (liraglutide) — a daily GLP-1 injection, another licensed option in the UK.
Eligibility typically requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions like type 2 diabetes or high blood pressure. Use our free GLP-1 weight loss calculator to explore potential outcomes with prescription medication, and our BMI calculator to check where you stand against NHS guidelines.
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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.
NHS Support and How to Access Weight Management in the UK
The NHS supports sustainable weight loss through a four-tier system. Tier 1 includes self-help and community programmes; Tier 2 involves your GP discussing behaviour change; Tier 3 is specialist weight management services where prescription medications may be offered; and Tier 4 covers bariatric surgery for severe obesity.
Access and waiting times vary significantly by region. Speak to your GP about referral to specialist services in your area, or explore private options through UK-licensed prescribers if NHS services are unavailable. A prescriber will assess whether prescription weight loss medication is suitable based on your individual health, BMI, and medical history. Track your progress using our free progress tracker whether you choose dietary changes, medication, or a combination approach.
- 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.
Is a 1200 calorie meal plan safe?
A 1200 calorie diet is classified as a low calorie diet (LCD) and should only be followed under medical supervision. The NHS recommends safer weight loss of 0.5–1 kg per week, typically requiring a 500 calorie daily deficit. Very low calorie diets can cause nutrient deficiencies, muscle loss, and fatigue. Speak to your GP before starting any restrictive diet.
What is the difference between 1200 calories and prescription weight loss medication?
A 1200 calorie meal plan is a dietary approach requiring significant restriction. Prescription medications like Mounjaro and Wegovy work alongside dietary changes to reduce appetite and support weight loss naturally. Medication may help you feel fuller on normal portions, whereas 1200 calories requires constant restriction. Both work best combined with lifestyle changes.
Who is eligible for prescription weight loss medication in the UK?
Adults with a BMI of 30 or above, or 27–29.9 with weight-related health conditions (type 2 diabetes, high blood pressure, sleep apnoea, etc.), may be eligible. Eligibility is assessed individually by a prescriber following a clinical assessment. Your GP can refer you to specialist weight management services, or you can seek private prescribing through UK-licensed providers.
How much weight can you lose on prescription weight loss medication?
Clinical trials show average weight loss of 15–21% of body weight with Mounjaro and around 15% with Wegovy — but individual results vary significantly. Weight loss is achieved alongside reduced-calorie diet and increased physical activity. Use our GLP-1 weight loss calculator to explore potential outcomes based on your starting weight and the medication dose.
Should I try a 1200 calorie diet or ask my GP about prescription options?
Both approaches require GP guidance. A 1200 calorie diet should only be supervised by a healthcare professional. If you meet eligibility criteria (BMI 30+, or 27–29.9 with health conditions), prescription medication may be a safer, more sustainable option. Speak to your GP about what's appropriate for your situation — they can assess your health, discuss options, and refer you to specialist services if suitable.
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.