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
What to Do If You're Overeating on Mounjaro
Mounjaro is designed to reduce appetite and help you feel fuller, but some people on this prescription medication still struggle with overeating. This may happen if your dose is too low, your body needs time to adjust, or if certain foods still trigger cravings. If you're experiencing difficulty controlling your eating whilst taking Mounjaro in the UK, understanding why this happens and what steps to take can help you get better results. Your GP or prescriber can adjust your treatment plan to support your weight management goals.
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.
Why Overeating Happens on Mounjaro
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist that works by signalling to your brain that you're full and reducing cravings. However, overeating can still occur for several reasons:
- Dose too low: Your current dose may not be providing enough appetite suppression for your individual needs. Mounjaro dose titration happens over several weeks — starting at 2.5 mg and increasing every 4 weeks up to the maximum 15 mg. If you're still hungry, you may not have reached your optimal dose yet.
- Adjustment period: Your body may need time to adapt to the medication. Side effects like nausea often decrease after a few weeks, which can restore appetite.
- Trigger foods: Some foods — particularly high-fat, high-sugar items — may bypass the appetite-suppressing effect, especially in the early weeks of treatment.
- Emotional or habitual eating: Mounjaro reduces physical hunger but doesn't address emotional eating patterns or established eating habits.
- Medication interaction: Certain other medications or health conditions may affect how well Mounjaro works for you.
If you're prescribed Mounjaro through the NHS or private route in the UK, your prescriber monitors your progress and can adjust your dose or treatment approach.
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 You Should Do If Overeating Persists
Contact your GP or prescriber if you're overeating despite being on Mounjaro. They may:
- Increase your dose to the next level (if you haven't reached maximum yet)
- Review your eating patterns and provide behaviour change support
- Check for underlying issues like gastroparesis or medication interactions
- Discuss whether continued treatment is appropriate for you
In the meantime, support your weight management by keeping a food diary, eating slowly, staying hydrated, and choosing whole foods over processed options. Use our free GLP-1 weight loss calculator to track your projected progress, and log your journey with our progress tracker to identify patterns. Never stop Mounjaro without consulting your prescriber — stopping abruptly can lead to rapid weight regain.
- 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.
Can Mounjaro stop working after a few weeks?
Mounjaro doesn't usually stop working, but appetite suppression may seem less noticeable as your body adapts and nausea reduces. This is normal. Your prescriber may increase your dose during the titration phase to maintain the appetite-suppressing effect. Individual response varies, and some people need higher doses than others.
Is overeating on Mounjaro a sign the medication isn't right for me?
Not necessarily. If you're in the early weeks or on a low dose, appetite suppression should improve as you increase doses. However, if you're on a stable, therapeutic dose (10–15 mg) and still overeating significantly, discuss this with your GP or prescriber. They can assess whether Mounjaro is the best option for your situation.
Should I eat less food on Mounjaro to force weight loss?
No. Mounjaro is designed to help you naturally eat less without extreme restriction. Forcing undereating can backfire and isn't sustainable. Trust the medication to reduce appetite, and focus on balanced meals. If appetite suppression isn't strong enough, your prescriber can adjust your dose rather than you restricting further.
Can I switch from Mounjaro to Wegovy if I'm overeating on Mounjaro?
Possibly, though this would be a decision for your prescriber. Wegovy (semaglutide) is a single GLP-1 agonist, whereas Mounjaro is a dual GIP and GLP-1 agonist. Clinical trial data suggests Mounjaro may offer slightly more weight loss on average, but individual response varies. Your prescriber can discuss whether switching makes sense for your circumstances.
How long does it take for Mounjaro appetite suppression to kick in?
Many people notice reduced appetite within the first few days of their first dose, though not everyone does. Appetite suppression typically increases as your dose increases during titration. If you're still not feeling the appetite-suppressing effect after 8–12 weeks on a higher dose, contact your prescriber for support and reassessment.
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.