Today, let’s dive into a topic that’s both super popular and a bit controversial: fasting, especially when you have a thyroid condition like Hashimoto’s. Is fasting a big "NO," or something you should seriously consider? Let's break it down!
The Science of Fasting with Hashimoto’s
Fasting is everywhere these days—you've probably thought about trying it yourself. But if you’ve ever Googled "thyroid and fasting," you’ve likely seen all the warnings. The internet can make it sound like fasting is a terrible idea for anyone with thyroid issues. So, what's the truth?
As with most things, the answer is... it really depends on where you're at in your healing journey.
If fasting isn’t done with careful consideration of your thyroid condition—and especially your female physiology—it can cause problems. Think: thyroid hormone imbalances, cortisol spikes, and disrupted sex hormones. But when done right, fasting can be a powerful tool. It might just transform your healing journey, support weight loss, improve your metabolism, balance blood sugar, and even boost longevity. It’s also worth noting that fasting is how our ancestors ate; food wasn’t always available, and our bodies haven’t changed that much. So, fasting in moderation can tap into those natural processes that allow for cellular repair and metabolic benefits.
Fasting, when done correctly, isn’t about long-term calorie restriction or depriving your body. It’s about creating strategic windows where your body can shift into repair mode.
Key Benefits of Fasting for Women with Hashimoto’s
1. Improved Insulin Sensitivity: Fasting helps your body use insulin more effectively, which can lower the risk of type 2 diabetes, reduce cholesterol levels, and stabilise blood pressure.
2. Blood Sugar Balance: When you practice regular fasting, it helps regulate your blood sugar levels. This is particularly helpful for reducing inflammation, managing cortisol, and keeping your energy steady throughout the day.
3. Reduced Inflammation: Studies show fasting can decrease inflammation throughout the body, which is key when managing autoimmune conditions like Hashimoto’s.
4. Autophagy: This is your body’s natural way of clearing out damaged cells and regenerating new ones. Fasting boosts autophagy, potentially slowing the aging process and helping prevent disease.
5. Weight Loss and Metabolic Flexibility: Fasting encourages your body to switch to burning fat for fuel. It also lowers insulin, which can speed up metabolism, making fasting an effective weight loss strategy—but only when done correctly! Lowering insulin can also optimise your oestrogen levels, if you're looking to improve ovulation.
The Best Types of Fasting for Women
The fasting method I recommend for most women with Hashimoto’s is Time Restricted Eating (TRE) and fasting in tune with your menstrual cycle. This means fasting from the last time you ate in the evening until your first meal the following day, aiming for at least 12 hours of fasting overnight. TRE is gentle on your body but provides big benefits for blood sugar, insulin, inflammation, leptin, and your circadian rhythm. Fasting in tune with your cycle means switching the lengths of your fasts to accommodate ovulation, detoxification, and most importantly for women with thyroid issues - maximising progesterone production.
As your thyroid and adrenal health improve, you can try longer fasts. I teach my clients to start with 12-13 hours. Then you can try extended fasts, fasts to take you into autophagy and fasts to re-set your neurotransmitters and then ultimately an occasional fast that you can do to heal your leaky gut. There are even longer fasts that really help with weight loss, but as I almost always see women at the beginning of their journey, I don't cover or recommend these kinds of fasts.
I cover essential fasting approaches in my Hashimoto’s Reset Programme, so if you'd like to learn how to eat and live in tune with your menstrual cycle in combination with a healing strategy then I would encourage you to sign up to my waitlist here and I will get in touch when spaces become available.
Important Considerations for Women Fasting with Hashimoto’s
Before you jump into fasting, there are a few essential things to keep in mind:
Don’t jump straight into long fasts: Ease yourself into it. You need to get your body used to producing ketones. Start with 12-13 hour overnight fasts before moving up to longer periods. Your body needs time to adjust.
Fasting won’t fix a poor diet: You need a thyroid-supportive, nutrient-rich diet as your foundation before adding fasting. The way you "break" your fast and structure meals during your eating window matters just as much as the fast itself.
Fasting is not the same for women as it is for men: Our hormones fluctuate, and fasting needs to align with that. A general rule: the 10 days before your period is when we should be 'feasting' and eating particular foods to help our bodies produce progesterone, so it is a "no-fasting" zone.
Don’t fast if you’re at the beginning of your healing journey: If you’re still struggling with severe fatigue, brain fog, or other intense symptoms, focus on building a strong foundation first. Optimise your nutrition, balance your lifestyle, and calm your nervous system. Fasting can come later when your body is ready and in better balance.
Listen to your body: If your body tells you fasting is too stressful, listen. If you’re dealing with adrenal fatigue or extreme fatigue, you may need to heal your blood sugar balance first before adding fasting to your routine. If you're getting headaches and don't find it easy, then you may need to troubleshoot.
Too high or too low cortisol? I would wait and rebalance your nervous system first. Eat regular, nutrient rich meals, get plenty of sleep and exercise gently. If you're also in a place of overwhelm, it's not worth stressing out over this, you can heal in other ways first.
Fasting as a Tool for Thyroid and Autoimmune Health
I’ve recently aligned my fasting routine with my menstrual cycle and have noticed not only how my body’s needs change throughout the month, but also some great benefits—like an increase in my T3 levels. While some claim fasting can lower T3, research shows this dip is temporary, occurring only during the fast. Once you break the fast, T3 levels often rebound, sometimes rising higher than before.
Overall, when done properly, fasting can be a powerful tool—not just for supporting thyroid and metabolic health, but also for improving autoimmune health.
If you're inspired to try fasting as part of your healing, I’d love to guide you through it in my Hashimoto's Reset Programme. We’ll start with the basics, so that you can get some big benefits without any overwhelm. Then if you'd like a more bespoke and
tailored fasting plan that works for your body and your autoimmunity we can work on this together.
I want to show you how you can naturally bring fasting into your lifestyle, so that it's easy, beneficial and in tune with your body. This is not a diet or punishment, just a way to unlock your body's natural healing mechanisms and potential.
So again, if you'd like to join the waitlist for my Hashimoto's Reset Programme you can do that here. Or book a call to discuss your health here:
Let’s reset your health and metabolism together!
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