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
Two Week Weight Loss Plan: What's Realistic?
A two week weight loss plan can help jumpstart your weight management journey, but realistic expectations are important. The NHS recommends losing no more than 0.5–1 kg (1–2 lbs) per week for sustainable results. Over two weeks, this means aiming for 1–2 kg of weight loss, not dramatic changes. Combining dietary changes, increased physical activity, and in some cases prescription weight loss medication, can support steady progress. This guide covers practical strategies aligned with NHS weight management guidance and explains how prescription options like GLP-1 medications fit into a broader two week weight loss plan.
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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.
Safe Weight Loss Rate and What to Expect
The NHS safe weight loss rate is 0.5–1 kg per week, which translates to approximately 1–2 kg over a two week period. This may sound modest, but research shows it's the rate most likely to lead to sustained weight loss rather than rapid regain.
To lose weight safely, you need a calorie deficit of around 500 kcal per day, which typically results in 0.5 kg per week. This can be achieved through:
- Reducing food intake (without extreme restriction)
- Increasing physical activity
- Combining both approaches
Very gradual weight management (more than 1.5 kg per week) increases the risk of muscle loss, nutritional deficiencies, and weight regain. If you're looking to use prescription weight loss medication as part of your two week weight loss plan, medication works best alongside reduced-calorie diet and exercise — not instead of them.
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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.
Two Week Weight Loss Plan with Prescription Options
For adults struggling with weight management in the UK, GLP-1 medications like Wegovy and Mounjaro are prescription-only options that may support weight loss when combined with lifestyle changes. These medications help reduce appetite and may support feeling fuller after smaller meals.
In clinical trials, GLP-1 medications like semaglutide (Wegovy) helped participants lose an average of around 15% of their body weight over several months — though individual results vary significantly. Access in the UK is through NHS specialist weight management services (tier 3) or private online prescribing following a clinical assessment. Use our free GLP-1 weight loss calculator to explore potential outcomes, and our BMI calculator to check where you currently stand against NHS healthy weight guidelines.
- 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 in two weeks?
The NHS recommends losing 0.5–1 kg per week safely, so realistically 1–2 kg over two weeks. This may sound modest, but it's the rate most likely to lead to lasting weight loss rather than rapid regain. Faster loss often leads to muscle loss and increased hunger later.
What should a two week weight loss plan include?
A balanced plan combines: reduced-calorie eating (around 500 kcal deficit per day), increased physical activity (walking, strength training), adequate water and sleep, and stress management. Focus on whole foods, protein-rich meals, and vegetables to stay satisfied on fewer calories.
Can prescription weight loss medication help with a two week plan?
Yes. Medications like Wegovy (semaglutide) and Mounjaro (tirzepatide) are prescription-only and may support appetite reduction when combined with diet and exercise. They're not quick fixes but can help establish healthier eating patterns over weeks and months. Requires clinical assessment first.
Should I follow a very low calorie diet for two weeks?
No. Very low calorie diets (under 800 kcal/day) carry risks including muscle loss, nutrient deficiency, and fatigue. They should only be done under medical supervision. The NHS recommends moderate, sustainable calorie reduction (500 kcal/day deficit) instead.
What's the difference between weight loss for two weeks versus a longer plan?
Two weeks is too short to assess lasting weight loss trends — many factors affect daily weight (water retention, food volume, hormones). Weight loss should be measured over 4–8 weeks minimum. A two week plan is best viewed as a starting point, not a complete programme.
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.