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
Juice Diet and Weight Loss — What the Evidence Shows
Juice diets are popular as a quick weight loss method, but evidence suggests they're not the most effective or sustainable approach for long-term weight management in the UK. While juicing can be part of a healthy diet, relying solely on juice removes essential nutrients like fibre, protein, and healthy fats. This guide explains how juice diets affect weight loss, compares them to evidence-based approaches, and explores what actually works for sustainable weight loss according to NHS guidance.
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.
How Juice Diets Affect Weight Loss
Juice diets create a calorie deficit, which is why people often lose weight quickly in the first few days. However, most of this initial loss is water weight and glycogen depletion, not fat loss. Freshly pressed or bottled juices are high in natural sugars and calories — a single 250ml glass of orange juice contains around 110 kcal and 26g of sugar, with virtually no fibre.
The NHS recommends a sustainable weight loss rate of 0.5–1 kg per week, achieved through a modest calorie deficit of around 500 kcal daily. Juice-only diets often create much larger deficits (1,000–2,000 kcal or more), which can lead to:
- Rapid initial weight loss followed by a plateau
- Muscle loss (not just fat loss)
- Blood sugar spikes and crashes
- Hunger and fatigue
- High likelihood of regaining weight once normal eating resumes
Most people cannot sustain juice diets long-term because they lack protein and healthy fats, which keep you feeling full.
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.
What Actually Works for Weight Management
Evidence-based approaches to weight management in the UK include reduced-calorie balanced diets (including whole foods), increased physical activity, and behavioural changes. The NHS Weight Loss Plan supports this with free digital tools and expert guidance. For eligible adults with a BMI of 30 or above, or 27+ with weight-related health conditions, prescription weight loss medication combined with lifestyle changes can provide significant support. GLP-1 medications like semaglutide (Wegovy) work by reducing appetite and helping you feel fuller — they're used alongside dietary changes, not instead of them. Use our free BMI calculator to check your current BMI and our GLP-1 weight loss calculator to explore how medication might support your weight management journey.
- 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.
Will I lose weight on a juice diet?
Yes, initially — typically 2–5 kg in the first week — but most is water weight. Juice diets create a large calorie deficit, which leads to rapid loss, but this is rarely sustainable. Most people regain weight once they return to normal eating because the diet doesn't address eating habits or include filling foods like protein and fibre.
Is juice diet safe long-term?
No. Juice-only diets lack essential nutrients like protein, fibre, healthy fats, and many micronutrients. Extended juice fasting can cause muscle loss, fatigue, nutrient deficiencies, and blood sugar problems. The NHS does not recommend juice diets as a weight loss method — balanced, whole-food diets are safer and more effective.
How does juice diet compare to other weight loss methods?
Juice diets create rapid initial loss but are unsustainable and don't teach healthy eating habits. NHS-supported approaches like calorie-controlled balanced diets, intermittent fasting (in moderation), and Mediterranean-style eating produce slower but lasting results. For eligible adults, prescription weight loss medication combined with lifestyle changes offers evidence-based support with clinical oversight.
Can I use juice as part of a healthy weight loss plan?
Yes, in moderation. A small glass of fresh juice (150ml) can count toward your daily fruit intake, but whole fruits are better because they include fibre. Focus on whole vegetables, lean proteins, and healthy fats for sustainable weight loss. Our weight converter and progress tracker help you monitor your weight and see what works for your body.
What's the best way to lose weight according to NHS guidance?
The NHS recommends a balanced diet with a 500 kcal daily deficit for 0.5–1 kg weekly loss, increased physical activity, and behaviour change support. For some people, prescription weight loss medication (like GLP-1 injections) combined with dietary changes is appropriate. Use our free BMI calculator to check your starting point and discuss options with your GP.
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.