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
Diet And Nutrition Plans For Weight Loss
Effective weight loss combines the right nutrition plan with consistent lifestyle changes. In the UK, the NHS recommends sustainable approaches that create a calorie deficit of around 500 kcal per day, supporting weight loss of approximately 0.5 to 1 kg per week. This guide covers evidence-based diet strategies, meal planning approaches, and when professional support — including prescription weight loss medication — may complement your efforts. Whether you're managing weight management uk goals alone or alongside medical support, understanding nutrition fundamentals is essential for long-term success.
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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.
Evidence-Based Diet Approaches For Weight Management
Several evidence-based nutrition plans have proven effective for sustainable weight loss. The Mediterranean diet combines whole grains, healthy fats, and vegetables — research shows strong cardiovascular benefits alongside weight management. Low-calorie diets (1200–1500 kcal daily) create consistent deficits, while intermittent fasting approaches like 5:2 or 16:8 may suit some individuals. Low-carbohydrate plans can support rapid initial loss, though long-term outcomes match standard calorie restriction.
The key principle: sustainable weight loss requires a calorie deficit — typically 500 kcal below your daily needs. Use our free BMI calculator to understand your current weight status, then work with a nutritionist or your GP to establish realistic targets. The NHS Weight Loss Plan offers free structured support through Tier 1 services in many areas. Results vary based on adherence, baseline weight, and individual metabolism — rapid loss isn't always healthier than gradual, consistent progress.
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.
Nutrition Plans Alongside Weight Loss Medication
For some individuals, prescription weight loss medication like Mounjaro or Wegovy supports progress when combined with dietary changes. These GLP-1 weight loss medications work by reducing appetite and food cravings, not replacing nutrition knowledge. Even with medication support, a structured nutrition plan remains essential — medications work best alongside reduced-calorie diet and increased physical activity. Our free GLP-1 weight loss calculator helps estimate potential results at different medication doses, but a prescriber will assess whether weight loss medication is appropriate for you based on your individual health.
Whichever approach you choose — whether through diet alone, nhs weight loss services, or prescription weight loss uk support — consistency matters more than perfection. Track your progress with our free progress tracker, adjust your plan based on results after 4–6 weeks, and maintain realistic expectations. Weight loss isn't linear, and plateaus are normal. Professional guidance from your GP, a registered dietitian, or a specialist weight management clinic helps ensure your approach is safe and sustainable for your circumstances.
- 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 best diet plan for weight loss?
No single plan works for everyone. The NHS recommends approaches that create a sustainable calorie deficit: Mediterranean diet, intermittent fasting, or low-carbohydrate plans all show evidence of effectiveness. The "best" plan is one you can stick to long-term. Aim for 0.5–1 kg loss weekly. Consult your GP or a registered dietitian for personalised guidance tailored to your health and lifestyle.
How many calories should I eat to lose weight?
Most weight loss requires approximately 500 kcal below your daily needs, supporting roughly 0.5 kg (1 lb) weekly loss. Individual calorie needs vary based on age, height, weight, sex, and activity level. The NHS recommends 1200–1500 kcal for women and 1500–1900 kcal for men as safe minimum levels. Always consult your GP before starting a very low-calorie diet.
Can I use weight loss injections instead of dieting?
Weight loss medications like Wegovy or Mounjaro are prescription-only and work best alongside dietary changes, not as replacements. These GLP-1 medications reduce appetite but require clinical assessment and a prescriber's decision. NHS access is through specialist weight management services; private prescribing is also available. Medication supports progress but doesn't eliminate the need for nutrition planning.
What's the difference between low-carb and low-calorie diets?
Low-calorie diets focus on total energy intake (typically 1200–1500 kcal daily). Low-carbohydrate diets restrict carbs, which may reduce appetite and support faster initial weight loss. Research shows long-term outcomes are similar — both require consistent adherence. Choose based on which approach feels sustainable for your lifestyle. Discuss any major dietary change with your GP first.
How quickly will I lose weight on a diet plan?
The NHS recommends losing 0.5–1 kg (1–2 lbs) per week as a safe, sustainable rate. Very rapid loss increases muscle loss risk and isn't recommended without medical supervision. Weight loss isn't always linear — plateaus are normal and usually temporary. Factors including genetics, medical conditions, stress, and sleep all affect progress. Track results over 4–6 weeks rather than day-to-day fluctuations.
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.