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 — Evidence-Based UK Guide
Not all carbohydrates affect weight loss equally. When managing your weight in the UK, understanding which carbs support your goals—alongside diet, exercise, and where appropriate, prescription weight loss medication—can make a real difference. This guide explains the science behind carbohydrate choices and how they fit into effective weight management for UK adults.
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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 Carbs Support Weight Loss?
The best carbs for weight loss are typically low glycaemic index (GI) foods that digest slowly, keeping you fuller for longer. These include:
- Oats and barley — high in soluble fibre, which slows digestion
- Sweet potatoes and legumes — beans, lentils, and chickpeas have excellent fibre-to-calorie ratios
- Whole grain bread and brown rice — more fibre and nutrients than refined versions
- Vegetables and whole fruits — high volume, low calorie density, nutrient-dense
Avoid or limit refined carbs: white bread, sugary cereals, biscuits, and sweetened drinks. These are calorie-dense, digest quickly, and don't support satiety. When aiming for weight management in the UK, the NHS recommends balancing carbohydrate intake with protein and healthy fats to maintain a calorie deficit. Using our free BMI calculator can help you understand your current weight status and set realistic goals.
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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.
Carbs and Weight Loss Medication
If you're considering GLP-1 weight loss medication (such as Wegovy or Mounjaro), carbohydrate choice becomes even more important. These prescription-only medicines work by slowing gastric emptying and reducing appetite, meaning smaller portions feel satisfying. Quality carbs—those high in fibre and nutrients—help prevent nutrient deficiencies when eating less overall.
Protein intake also rises in importance alongside weight loss medication. The NHS and clinical research emphasise that prescription weight loss treatment works best when combined with sustained dietary changes and increased physical activity. Our GLP-1 weight loss calculator can help you explore potential outcomes with medication, though individual results vary significantly.
- 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.
Are carbs bad for weight loss?
No. Carbohydrates aren't inherently bad for weight loss—the type and portion matter. Low GI carbs (oats, legumes, whole grains) support satiety and stable blood sugar. Refined carbs (white bread, sugary foods) spike blood sugar and hunger. A balanced approach with appropriate portion control supports sustainable weight loss in the UK.
How many carbs should I eat daily for weight loss?
The NHS doesn't prescribe a fixed carb amount—it depends on your individual calorie deficit target. Most sustainable weight loss involves reducing total calories by 500 kcal daily (roughly 0.5 kg/week loss). A typical approach is 45–65% of daily calories from carbs, emphasising whole grains and vegetables. Your GP or a registered dietitian can advise based on your personal health.
Can I lose weight with GLP-1 medication and carbs?
Yes. GLP-1 medications (prescription-only, requiring clinical assessment) work alongside dietary changes. Lower carb portions feel more satisfying due to how these medicines slow digestion. Focus on nutrient-dense, high-fibre carbs to avoid nutrient gaps when eating less overall. Individual results vary; always follow prescriber guidance.
What's the difference between simple and complex carbs?
Simple carbs (sugars, refined grains) digest quickly and spike blood sugar, increasing hunger shortly after. Complex carbs (whole grains, legumes, vegetables) contain fibre, digest slowly, and support sustained energy and satiety. For weight loss, complex carbs are consistently preferable. They're also linked to better long-term health outcomes.
Should I cut carbs completely to lose weight?
No. Very low carb diets can work short-term but are hard to sustain. The NHS recommends moderate, sustainable approaches over extreme restriction. Cutting all carbs risks nutrient deficiencies and muscle loss. A balanced diet with quality carbs, adequate protein, and healthy fats—alongside regular activity—supports lasting weight management in the UK.
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.