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
Is Watermelon A Good Weight Loss Food?
Yes, watermelon can be a useful addition to a weight loss diet, though it's not a clinically supported solution on its own. Watermelon is around 92% water and contains only about 30 calories per 100g, making it one of the lowest-calorie fruits available. It can help you feel fuller for longer whilst keeping your overall calorie intake down—a key principle in sustainable weight loss. However, weight loss ultimately depends on creating and maintaining a calorie deficit through balanced nutrition and physical activity. If you're interested in tracking your progress, our free BMI calculator can help you establish your baseline and monitor improvements over time.
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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.
Why Watermelon Works For Weight Loss
Low calorie density: At just 30 calories per 100g, watermelon is significantly lower in calories than most other fruits. A whole slice (around 300g) contains only about 90 calories, meaning you can eat a generous portion without exceeding your calorie allowance.
High water content: The 92% water composition helps create volume in your stomach, signalling fullness to your brain. This can reduce overall food intake and help prevent overeating during meals.
Natural fibre: Watermelon contains fibre, which supports digestive health and can enhance feelings of satiety. This makes it easier to stick to a calorie deficit without constant hunger.
No added sugar in whole fruit: Unlike many processed weight loss foods, fresh watermelon contains only natural sugars balanced with water and fibre—avoiding blood sugar spikes that trigger cravings.
However, weight loss ultimately requires a sustained calorie deficit alongside regular physical activity. Watermelon alone won't produce weight loss without these broader dietary changes. Many people in the UK working towards weight management find success through a combination of dietary adjustments, increased movement, and where appropriate, prescription weight loss medication following clinical assessment.
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.
How To Use Watermelon In Your Weight Loss Plan
Watermelon works best as part of a balanced, calorie-controlled diet rather than as a standalone food. Include it as a filling, low-calorie snack between meals, or use it to add volume to meals without significantly increasing calories. A typical serving—one slice or around 300g—fits comfortably into most weight loss diets.
Avoid watermelon juice without pulp, as juicing removes fibre and concentrates natural sugars, making it easier to overconsume calories. Whole watermelon pieces are always the better choice.
For sustained weight loss results, combine watermelon with: whole grains, lean protein sources, and regular physical activity. The NHS recommends losing no more than 0.5–1 kg per week for sustainable outcomes. Our free weight converter and BMI calculator can help you set realistic targets and track your progress effectively throughout your weight loss 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.
How many calories are in watermelon?
Watermelon contains approximately 30 calories per 100g, or roughly 90 calories per slice (300g). This makes it one of the lowest-calorie fruits available, suitable for most weight loss diets.
Can watermelon alone help me lose weight?
No. Watermelon can support weight loss as part of a calorie-controlled diet, but weight loss requires a sustained calorie deficit overall. Watermelon is best used as a low-calorie snack or meal addition, not as a replacement for balanced nutrition.
Is watermelon juice better for weight loss than whole watermelon?
No. Watermelon juice lacks fibre and concentrates natural sugars, making it easier to overconsume calories. Whole watermelon pieces are significantly better for weight loss because the fibre content helps you feel fuller for longer.
What's the best time to eat watermelon for weight loss?
Watermelon works well as a mid-morning or afternoon snack to prevent overeating at meals. Its high water content can create feelings of fullness, making it useful before meals if you struggle with portion control.
Does watermelon count towards my daily calorie intake?
Yes. Whilst watermelon is low in calories, it still counts towards your daily total. At 30 calories per 100g, it's easy to include without significantly impacting a calorie-controlled diet, but portion awareness remains important.
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.