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 Overeat On Mounjaro
Overeating while taking Mounjaro can happen, especially in the early weeks of treatment or when doses are being adjusted. Unlike some expectations, Mounjaro doesn't completely eliminate hunger—it helps reduce cravings and supports feeling fuller after smaller meals. If you find yourself overeating, the good news is this is manageable and common. Understanding why it's happening and what steps to take can help you get back on track with your weight management goals.
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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 Overeating Can Happen On Mounjaro And What To Do
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist that works by signalling satiety to the brain, but it's not a complete appetite suppressant. Several factors can lead to overeating whilst on Mounjaro:
- Dose adjustment phase: During dose titration, appetite suppression effects may vary week to week. If you're between dose increases, you might experience slightly more hunger as your body adjusts.
- Food choices: Mounjaro works best with nutrient-dense, lower-calorie foods. High-calorie, high-fat, or sugary foods can be consumed in larger quantities without triggering the same satiety signal.
- Emotional eating: Medication helps with physical hunger but doesn't address eating triggered by stress, boredom, or habit.
- Gastroparesis adaptation: The slowing of gastric emptying—especially noticeable in early weeks—often improves over time, meaning food moves through your stomach faster again.
If you're overeating, start by reviewing portion sizes and food quality rather than assuming the medication has stopped working. Keep a food diary for 3–5 days to identify patterns. Contact your GP or the NHS specialist tier 3 weight management service that prescribed your Mounjaro if overeating is frequent or leading to discomfort.
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.
Managing Portion Control And Side Effect Relief
Practical steps to prevent overeating on Mounjaro:
- Eat slowly and mindfully: Put your fork down between bites. Satiety signals can take 15–20 minutes to reach your brain.
- Measure portions before eating: Use a smaller plate or bowl, or pre-portion meals to avoid automatic overeating.
- Stay hydrated: Thirst is sometimes confused with hunger. Drink water throughout the day.
- Avoid trigger foods: Foods that are easy to overeat (crisps, biscuits, takeaway) should be limited or removed from your home.
- Increase fibre: Vegetables, legumes, and wholegrain foods increase satiety and support the appetite-suppressing effects of tirzepatide.
If overeating is accompanied by severe nausea, stomach pain, or vomiting, contact your GP immediately—these may indicate a complication like gastroparesis that needs medical attention.
- 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.
Is overeating on Mounjaro a sign the medication isn't working?
Not necessarily. Mounjaro reduces appetite and helps you feel fuller, but it's not a complete hunger blocker. Overeating can happen due to food choices, portion control habits, or dose adjustment phases. If appetite suppression was noticeable before and has disappeared, contact your GP—your prescriber may adjust your dose or review your treatment.
Should I stop taking Mounjaro if I overeat?
No. Stopping Mounjaro won't help. Instead, review your eating patterns, portion sizes, and food quality. Keep a food diary to identify triggers. If overeating is frequent or you're experiencing severe side effects, contact your NHS specialist weight management service or GP—they can advise on dose adjustments or strategies without stopping treatment.
Can I use the GLP-1 weight loss calculator to track what I should be eating on Mounjaro?
The GLP-1 weight loss calculator on MyWeightCheck estimates potential weight loss outcomes at different doses based on clinical trial data. However, for personalised dietary guidance whilst on Mounjaro, your NHS tier 3 weight management service or GP should refer you to a registered dietitian who can create a plan tailored to your Mounjaro dose and health goals.
How long does it take for Mounjaro to reduce appetite effectively?
Most people notice reduced appetite within 1–2 weeks of starting Mounjaro, with stronger effects as doses increase over 16–20 weeks of titration. Individual responses vary. If you haven't noticed appetite reduction by week 4 of your current dose, discuss this with your prescriber—they may recommend a dose increase or check for other factors affecting your response.
What's the difference between overeating on Mounjaro vs Wegovy if I'm considering switching?
Both Mounjaro and Wegovy are GLP-1 pathway agonists, but Mounjaro is a dual GIP and GLP-1 agonist, which some people find more effective. If overeating is a problem on one medication, it may relate to your individual response or dose rather than the drug itself. Your prescriber can discuss whether a dose adjustment or switch is appropriate based on NHS eligibility and your clinical needs.
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.