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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Nutrition Plan For Weight Loss — A UK Health Guide
A nutrition plan is essential for sustainable weight loss. Whether you're managing your weight through diet alone or alongside prescription medication like GLP-1 injections, eating the right foods in the right amounts matters. This guide explains how to build a personalised nutrition plan aligned with NHS weight management guidance, the calorie deficit approach that underpins healthy weight loss, and how nutrition fits into your overall weight loss journey in the UK.
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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.
Building Your Nutrition Plan — Key Principles
An effective nutrition plan for weight loss starts with understanding calorie deficit — the foundation of sustainable weight management in the UK. The NHS recommends losing 0.5 to 1 kg per week, which typically requires a daily calorie deficit of around 500 kcal. This means consuming approximately 500 calories fewer than you burn each day.
Your nutrition plan should include:
- Protein-rich foods — eggs, chicken, fish, legumes, yoghurt — which support muscle preservation and keep you fuller longer
- Fibre-rich foods — whole grains, vegetables, fruit, pulses — which aid digestion and satiety
- Healthy fats — olive oil, avocado, nuts, oily fish — which support hormone regulation
- Hydration — aim for 6 to 8 glasses of water daily
Check your BMI using our free BMI calculator above to understand your current weight status, then calculate your personal calorie target with your GP or a registered dietitian. If you're considering prescription weight loss medication like GLP-1 injections, your nutrition plan becomes even more important — these medicines work best alongside dietary changes and increased physical activity, 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.
Nutrition Plans and Weight Loss Medication
If you're exploring prescription weight loss options — such as Mounjaro (tirzepatide) or Wegovy (semaglutide) — your nutrition plan remains central to success. These GLP-1 medications may help reduce appetite and support feeling fuller after smaller meals, but they work most effectively when combined with healthy eating and exercise. Our GLP-1 weight loss calculator can help you estimate potential outcomes at different doses, alongside dietary changes.
Early side effects like nausea or reduced appetite may actually make it easier to stick to your nutrition plan initially. However, as your body adapts (usually within weeks), consistent, balanced eating becomes crucial. Work with your prescriber and consider asking for a referral to a dietitian through the NHS weight management pathway. Track your progress using our free progress tracker, monitor how different foods affect your energy and satiety, and adjust your nutrition plan based on what works for your body.
- 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 nutrition plan for weight loss in the UK?
The best nutrition plan is one you can sustain long-term. Start with a modest calorie deficit (around 500 kcal/day for 0.5 kg weekly loss), include adequate protein and fibre, and focus on whole foods. The NHS recommends consulting your GP or a registered dietitian for a personalised plan. If eligible, prescription weight loss medication may support your efforts alongside nutrition changes.
How many calories should I eat to lose weight?
Individual calorie needs depend on your age, sex, height, current weight, and activity level. Generally, a deficit of 500 kcal/day supports losing about 0.5 kg per week. Use our BMI calculator to check your current weight status, then discuss a safe calorie target with your GP. Very low-calorie diets (under 800 kcal/day) should only be followed under medical supervision.
Can GLP-1 medication replace a nutrition plan?
No. Prescription weight loss medicines like Mounjaro and Wegovy work best alongside a balanced nutrition plan and increased physical activity. These medications may help reduce appetite, but they're not a replacement for healthy eating habits. Think of them as a support tool — nutrition remains essential for sustainable weight loss and long-term health.
Should I follow a specific diet when taking weight loss injections?
There's no single "correct" diet, but focus on nutrient-dense, whole foods — lean proteins, vegetables, whole grains, and healthy fats. Early on, reduced appetite may make eating easier. As your body adapts, consistent balanced nutrition becomes important. Ask your prescriber about dietitian referral through NHS weight management services for personalised guidance.
How do I know if my nutrition plan is working?
Track your progress using our free progress tracker, weigh yourself weekly at the same time, and monitor how you feel — energy levels, hunger, mood. Aim for gradual, steady loss of 0.5–1 kg per week. If progress stalls, review portion sizes or speak with your GP. Remember, sustainable weight loss takes time; avoid crash diets.
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.