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
Best Carbs for Weight Loss
When it comes to weight loss in the UK, carbohydrate choice matters more than total elimination. Rather than cutting carbs entirely, selecting low glycaemic index (GI) carbohydrates and controlling portions can support sustainable weight management alongside increased physical activity. The NHS recommends a balanced approach that includes whole grains, legumes, and vegetables. Whether you're managing your weight independently or considering prescription weight loss support, understanding carbohydrate quality helps you make informed dietary choices that work with your lifestyle.
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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.
Which Carbohydrates Support Weight Loss?
The best carbohydrates for weight loss are typically low glycaemic index (GI) options that release energy slowly, helping you feel fuller for longer. These include:
- Whole grains: oats, brown rice, quinoa, wholemeal bread (aim for at least 30g fibre daily as per NHS guidance)
- Legumes: lentils, chickpeas, beans — high in protein and fibre, supporting satiety
- Vegetables: leafy greens, broccoli, sweet potatoes, carrots — nutrient-dense and low in calories
- Fruits: berries, apples, pears — contain natural sugars but high in fibre
Avoid refined carbohydrates like white bread, sugary cereals, and processed snacks, which cause rapid blood sugar spikes and increased hunger. A calorie deficit of around 500 kcal daily typically supports a loss of approximately 0.5 kg per week according to NHS weight management guidance. Use our free BMI calculator above to understand your personal healthy weight range and how carbohydrate choices fit into your overall nutrition plan.
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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.
Carbohydrates and Weight Loss Medication
If you're considering prescription weight loss medication as part of your weight management strategy in the UK, carbohydrate quality remains important. GLP-1 medications like semaglutide (Wegovy) work alongside dietary changes — they're not replacements for healthy eating. Evidence from clinical trials shows that combining prescription weight loss support with a balanced diet including appropriate carbohydrate choices produces better results than medication alone. Nausea is a common side effect of GLP-1 treatment, so choosing easily tolerated, nutrient-dense carbohydrates like plain rice or oatmeal during adjustment periods can be helpful. Our GLP-1 weight loss calculator can help you explore potential outcomes when combined with improved nutrition. Always discuss your dietary approach with your GP or prescriber before starting any weight loss medication.
- 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 difference between simple and complex carbohydrates for weight loss?
Simple carbohydrates (white bread, sugar, sweets) digest quickly, causing rapid blood sugar spikes and increased hunger. Complex carbohydrates (whole grains, legumes, vegetables) digest slowly, keeping you fuller longer and supporting more stable energy levels — making them better for sustainable weight management.
Should I eliminate carbohydrates completely to lose weight?
No — the NHS doesn't recommend eliminating carbs entirely. Instead, focus on quality and portion control. Whole grains, legumes, and vegetables provide essential nutrients, fibre, and energy. A balanced approach with reduced-calorie portions supports sustainable weight loss better than complete elimination, which is difficult to maintain long-term.
How much carbohydrate should I eat daily for weight loss?
There's no universal amount — it depends on your personal calorie target, activity level, and health. The NHS recommends about 230g of carbohydrates daily as part of a balanced diet, but for weight loss you may reduce this slightly. A registered dietitian can provide personalised guidance based on your health and goals.
Do carbohydrates affect GLP-1 weight loss medication?
GLP-1 medications like Wegovy work with your body's natural hunger signals regardless of carbohydrate choice, but nausea is common initially. Choosing gentle carbohydrates (plain rice, oatmeal, toast) during dose adjustments can help. Medication works best alongside dietary changes, not instead of them — quality carbs remain important.
Which carbohydrates have the lowest glycaemic index (GI)?
Low GI carbohydrates include: steel-cut oats, barley, lentils, chickpeas, most vegetables, and some fruits like apples and berries. These release energy slowly, supporting stable blood sugar and better appetite control during weight management. Check NHS resources for a full GI guide when planning meals.
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.