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
Easy Weight Loss Diet — A Practical UK Approach
There's no truly "easy" weight loss diet, but there are effective, sustainable approaches that work better than others. The most successful weight loss comes from a combination of dietary changes, increased physical activity, and sometimes prescription medication support. This guide explains evidence-based weight management strategies used in the UK, including NHS-approved methods and modern prescription options that may help you lose weight alongside lifestyle changes.
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.
What Actually Works for Weight Loss
The NHS recommends losing weight at a rate of 0.5 to 1 kg per week for sustainable results. This typically requires a calorie deficit of around 500 kcal per day. Several approaches have strong evidence behind them:
- Mediterranean diet: Emphasises whole grains, vegetables, olive oil, and fish — supported by strong evidence for both weight loss and cardiovascular health
- Low carbohydrate diet: Effective for short-term weight loss, though long-term results are similar to standard calorie restriction
- Intermittent fasting (16:8 or 5:2): Can support weight loss by naturally reducing overall calorie intake
- Calorie counting: Simple but effective — knowing your deficit is crucial for predictable weight loss
The best diet is the one you can actually stick to. Use our free BMI calculator above to understand your current weight status, and our weight converter to track progress in your preferred units (kg, stone, or lbs).
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 Diet Alone Isn't Enough — Prescription Support
For adults with a BMI of 30 or above, or BMI 27–29.9 with weight-related health conditions, prescription weight loss medication may be recommended. GLP-1 weight loss injections (such as Wegovy or Mounjaro) work alongside diet and exercise to help reduce appetite and support weight management. Clinical trials showed that GLP-1 medications may help lose an average of 14–21% of body weight — though individual results vary significantly.
These are prescription-only medicines requiring a clinical assessment from a GP or licensed prescriber. Try our GLP-1 weight loss calculator to estimate potential weight loss at different doses, and track your progress with our free progress tracker to monitor changes over time.
- 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's the easiest diet for weight loss?
The easiest diet is one you can sustain long-term. The Mediterranean diet has strong evidence for being both effective and realistic to follow. Aim for a modest calorie deficit (around 500 kcal/day) rather than extreme restriction — this supports steady weight loss of 0.5–1 kg per week without muscle loss or unsustainable hunger.
Can I lose weight without exercise?
Weight loss is primarily driven by calorie deficit, so diet alone can produce results. However, combining dietary changes with physical activity produces better long-term outcomes, improves fitness, and helps preserve muscle mass during weight loss. Even modest activity — like 30 minutes of walking daily — makes a meaningful difference.
Is prescription weight loss medication worth it?
GLP-1 medications like Wegovy or Mounjaro may help if diet and exercise alone aren't achieving results, particularly for those with a BMI over 30 or weight-related health conditions. These are prescription-only and used alongside lifestyle changes, not instead of them. Your GP can assess whether medication is appropriate for your individual situation.
How quickly should I expect to lose weight?
The NHS recommends aiming for 0.5–1 kg (1–2 lbs) per week for sustainable, healthy weight loss. Faster loss is possible but increases risk of muscle loss and is harder to sustain. Most people see noticeable changes within 4–6 weeks, but progress varies based on starting weight, diet adherence, and metabolism.
What's the difference between weight loss diets and NHS weight management?
NHS weight management through tier 3 specialist services offers structured support including behaviour change counselling, dietary guidance, and access to prescription medication if appropriate. Commercial diets focus primarily on food rules. NHS services provide medical oversight — important if you have health conditions or take other medications.
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.