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
Hypothyroidism Diet Plan For Weight Loss
Weight loss with hypothyroidism requires a different approach because a sluggish thyroid slows metabolism significantly. Unlike healthy adults, people with an underactive thyroid burn fewer calories at rest, making standard diet advice less effective. This guide explains evidence-based dietary strategies, thyroid-friendly nutrition, and when prescription weight loss support may help—alongside proper thyroid medication management with your GP.
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.
Dietary Strategies For Weight Loss With Hypothyroidism
Hypothyroidism slows your metabolic rate, meaning your body burns fewer calories during the day. This doesn't make weight loss impossible, but it requires a tailored approach:
- Prioritise protein at every meal—aim for 25–30g per meal. Protein has the highest thermic effect (your body burns calories digesting it) and helps preserve muscle during weight loss.
- Include selenium, zinc, and iron-rich foods—these minerals support thyroid function. Good sources: brazil nuts, pumpkin seeds, lentils, lean red meat, and fortified cereals.
- Avoid sudden extreme calorie restriction—very low-calorie diets can further suppress thyroid function. Aim for a modest deficit of 300–500 kcal daily.
- Time meals consistently—eat at regular intervals to support metabolic stability.
- Stay hydrated—adequate water intake supports metabolism and helps distinguish hunger from thirst.
Your GP should monitor your thyroid (TSH and T4 levels) regularly during weight loss, as calorie restriction may require thyroid medication adjustment.
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.
When Prescription Weight Loss Support May Help
If diet and exercise alone haven't produced results after 3–6 months, and your thyroid is well-controlled on medication, prescription weight loss medication may be suitable. GLP-1 weight loss injections like Wegovy work by reducing appetite and food cravings—addressing a key challenge for people with hypothyroidism, whose hunger signals may be dysregulated.
Eligibility depends on your BMI: adults with a BMI of 30 or above, or 27 or above with weight-related health conditions, may be considered for prescription weight loss. Always discuss options with your GP or a licensed prescriber. Use our free BMI calculator above to check your personal BMI, and our GLP-1 weight loss calculator can help project potential results if medication is appropriate for you.
- 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 you lose weight with hypothyroidism?
Yes, but it requires a tailored approach. Weight loss is slower with hypothyroidism because your metabolic rate is reduced by 15–40% depending on severity. Proper thyroid medication, adequate protein intake, and consistent calorie deficit (around 300–500 kcal daily) support sustainable loss. Your GP should monitor thyroid levels throughout.
What foods should I avoid with hypothyroidism and weight loss?
Avoid excessive raw cruciferous vegetables (cabbage, kale, broccoli) in large quantities, as goitrogens may interfere with iodine absorption when thyroid control is poor. Also limit ultra-processed foods high in sodium and added sugars. Focus on whole foods: lean protein, whole grains, vegetables (cooked preferred), and healthy fats.
How much weight can I lose with hypothyroidism?
Realistic weight loss is 0.25–0.5kg per week—slower than people without thyroid disease. This is safe and sustainable. A 5% reduction in body weight (around 4–5kg for most people) brings measurable health benefits even if you don't reach a "target" weight. Consistency matters more than speed.
Does hypothyroidism medication help weight loss?
Getting to the correct thyroid medication dose helps stabilise metabolism, but it typically doesn't cause weight loss on its own. It brings your metabolism back to normal baseline. Weight loss then requires a calorie deficit combined with diet, exercise, and possibly medical support.
Is prescription weight loss medication safe with hypothyroidism?
Prescription weight loss medications like GLP-1 injections can be safe with well-controlled hypothyroidism, but require assessment and monitoring by a GP or prescriber. Your thyroid medication dose may need adjustment. Never start any weight loss medication without medical review—discuss it with your GP first.
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.