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 Diet Coke Good for Weight Loss?
Diet Coke and similar zero-sugar fizzy drinks are often chosen by people trying to lose weight, but the evidence suggests they're unlikely to help with weight management UK. While diet drinks contain no calories, research indicates that artificial sweeteners may not support weight loss goals the way people hope. This guide explores what the evidence shows and outlines effective approaches to sustainable weight loss alongside nhs weight loss principles.
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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.
What Does the Research Show About Diet Drinks?
Several large studies have found that people who regularly consume diet drinks tend to gain more weight over time, not lose it. This counter-intuitive finding suggests diet drinks alone won't help with weight loss. Possible reasons include:
- Artificial sweeteners may not satisfy cravings — your brain recognises sweetness without calories, which could trigger hunger signals or cravings for more food later
- Diet drinks don't address calorie intake from other sources — swapping regular cola for diet cola saves calories but won't create the calorie deficit needed for weight loss
- Carbonation and caffeine may increase appetite in some people, though evidence varies
- Habit and behaviour patterns — people who drink diet colas often maintain other unhealthy habits that prevent weight loss
The key point: diet drinks are neutral at best, not helpful. Real weight loss depends on overall calorie intake and sustainable lifestyle changes, not on the type of fizzy drink you choose.
Clinically BackedWeight Loss
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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.
What Actually Works for Sustainable Weight Loss?
The NHS recommends losing weight at a rate of 0.5 to 1 kg per week through a combination of reduced-calorie diet and increased physical activity. A calorie deficit of around 500 kcal per day is the gold standard. For adults with a BMI of 30 or above — or 27 or above with weight-related health conditions — prescription weight loss medication may be appropriate. Use our free BMI calculator to check your personal BMI, and explore our GLP-1 weight loss calculator if you're interested in prescription weight loss injections uk. Your GP can discuss which approach suits your individual circumstances.
- 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.
Does Diet Coke have any calories?
No. Diet Coke contains zero calories and zero sugar. However, zero calories doesn't mean it supports weight loss. Research suggests regular diet drink consumption is linked to weight gain, likely due to how artificial sweeteners affect appetite and eating behaviour.
What's the difference between Diet Coke and regular Coke for weight loss?
Regular Coke contains about 140 calories and 39g sugar per 330ml can. Diet Coke has zero calories and zero sugar. Switching to diet versions saves calories in that drink, but studies show people who drink diet sodas often don't lose weight overall — the calorie saving may be offset by increased hunger or other dietary choices.
Are artificial sweeteners safe for weight loss?
Artificial sweeteners (aspartame, sucralose, etc.) are approved as safe by UK and European food authorities. However, evidence suggests they don't help with weight loss. Some research hints they may increase appetite or food cravings, though this varies between individuals. They're not harmful, but they're not a weight loss solution.
What should I drink instead if I'm trying to lose weight?
Water is best — it has zero calories and helps with hydration. Tea, coffee, and unsweetened beverages are also fine. The most important factor for weight loss is overall calorie intake from food, not drinks. Focus on reducing portion sizes and choosing nutrient-dense foods rather than worrying about diet drinks specifically.
Can prescription weight loss medication help if diet and exercise aren't working?
Yes. Prescription weight loss injections like semaglutide (Wegovy) are available through the NHS or private prescribing if you meet eligibility criteria. These medications work alongside dietary changes and physical activity — not as replacements. Your GP can assess whether you're a suitable candidate and discuss your options for effective prescription weight loss 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.