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
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Weight Loss With Diverticulitis
Losing weight while managing diverticulitis requires careful planning and medical guidance. Diverticulitis affects how your digestive system handles food, which means standard weight loss approaches may need adjustment. The good news is that sustainable weight loss is possible with the right support. This guide explains safe strategies, when to involve your GP, and how prescription weight loss medication might fit into your approach. Always consult your healthcare team before starting any weight loss programme if you have diverticulitis, as your individual circumstances matter greatly.
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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.
Diverticulitis and Weight Loss — What You Need to Know
Diverticulitis is inflammation in small pouches (diverticula) of the colon, often triggered by diet low in fibre or infection. During acute episodes, your GP typically recommends a liquid diet or clear foods to rest your digestive system. This means standard weight loss through calorie reduction needs careful timing—attempting aggressive weight loss during active diverticulitis can worsen symptoms.
Key considerations:
- Weight loss is safest between episodes, when your digestive system is stable
- gradual weight management may stress your colon and trigger flare-ups
- Increasing fibre gradually (not suddenly) is essential for prevention
- Your BMI matters for overall health, but managing diverticulitis comes first
- NHS guidance recommends working with your GP and possibly a dietitian specialist
Use our free BMI calculator to establish your baseline, then discuss realistic weight loss goals with your GP that account for your diverticulitis management plan.
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.
Prescription Weight Loss Options With Diverticulitis
GLP-1 weight loss injections like Wegovy (semaglutide) may theoretically support weight management in this situation, but diverticulitis requires special caution. These prescription medications slow gastric emptying—meaning food moves more slowly through your digestive system. For someone with diverticulitis, this delayed digestion could potentially trigger symptoms in some cases.
Any prescription weight loss treatment with diverticulitis must be assessed individually by your GP or gastroenterologist. They can evaluate whether the benefits outweigh risks for your specific situation. If prescribed, your prescriber will monitor you carefully. Standard NHS weight management support through tier 3 services is often the safer first approach, as it focuses on sustainable dietary change suited to your digestive health. Try our free GLP-1 weight loss calculator to understand potential outcomes, but always discuss options with your medical team first.
Practical Steps for Safe Weight Loss With DiverticulitisSustainable strategies that respect your digestive health:
- Work with an NHS-registered dietitian who understands diverticulitis—ask your GP for referral
- Increase fibre slowly and consistently once symptoms settle, not rapidly
- Stay hydrated and avoid trigger foods (fried, spicy, or low-fibre options)
- Aim for gradual weight loss of 0.5–1 kg per week, not faster
- Use our free progress tracker to log your weight and symptom patterns alongside dietary changes
- Be patient—flare-ups may pause weight loss temporarily, and that is normal
- Discuss any weight loss medication with your gastroenterologist before starting
Your GP can refer you to NHS weight management services at tier 1 or 2, where behaviour change support and dietitian guidance are tailored to your health needs—including diverticulitis management.
- 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 I lose weight safely if I have diverticulitis?
Yes, but weight loss timing and approach matter greatly. Between episodes, when your digestive system is stable, sustainable weight loss is achievable. Aim for gradual loss of 0.5–1 kg per week, alongside dietary management to prevent flare-ups. Always involve your GP or dietitian in your plan. During acute episodes, focus on managing symptoms first—weight loss can wait.
Are weight loss injections safe if I have diverticulitis?
This depends on your individual situation. GLP-1 injections like Wegovy are prescription-only and must be prescribed by a UK-licensed doctor following a clinical assessment. Your gastroenterologist needs to evaluate whether the delayed gastric emptying these medications cause could trigger your symptoms. For many people with diverticulitis, other approaches like NHS dietitian support may be safer first.
What diet should I follow for weight loss with diverticulitis?
During remission, a high-fibre diet supports both weight loss and diverticulitis prevention. Include plenty of vegetables, whole grains, legumes, and fruits. Increase fibre gradually—sudden changes can trigger flare-ups. Avoid low-fibre, fried, and spicy foods that may irritate your colon. A dietitian can personalise your plan to your specific triggers and weight loss goals.
Should I see my GP before trying to lose weight?
Absolutely. Always tell your GP about weight loss plans when you have diverticulitis, especially if you are considering prescription weight loss treatment. Your GP can assess whether timing is right, refer you to specialist support, and ensure your plan won't worsen symptoms. They may refer you to NHS weight management services or a gastroenterology dietitian.
How do I track progress safely while managing diverticulitis?
Use our free progress tracker to log your weight alongside symptom patterns and dietary changes. This helps you and your GP identify what works for your body. Weight loss may pause during flare-ups—this is normal and expected. Focus on sustainable progress rather than rapid loss. Regular GP check-ins help keep both weight management and diverticulitis under control.
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.