The Food Medic - Ask Dr. Hazel Wallace: Can Your Menstrual Cycle Sync with Your Friends? Exploring Menstrual Synchrony

Episode Date: June 11, 2025

In this solo episode of The Food Medic Podcast, Dr. Hazel Wallace, a renowned women's health nutritionist and former NHS doctor, speaks directly to the camera, delving into menstrual synchrony, the effects of fasted exercise on menstrual cycles, and managing PCOS. Alongside sharing expert advice, Dr. Wallace answers listener questions, grounding the discussion in real-life concerns and offering practical, accessible guidance. In this episode, Dr. Wallace answers: Is it true that our periods sync with people we spend time with, like our friends or family? Is fasted exercise bad for your menstrual cycle? Can you really heal PCOS holistically, and is the pill really that bad? Dr. Wallace provides evidence-based insights and practical advice, emphasising the importance of individualised care, balanced nutrition, appropriate physical activity, and stress management for improving PCOS symptoms. She also promotes her new book, ‘Not Just a Period,’ which offers a comprehensive guide to menstrual health. — If you have a question you'd like us to answer on the podcast, simply send a voice note to [e-mail] – we'd love to hear from you! Stay up to date with the latest health advice, recipes, insights, and updates from Dr. Hazel Wallace and The Food Medic community. Dr. Hazel Wallace Instagram: https://www.instagram.com/drhazelwallace/ The Food Medic Instagram: https://www.instagram.com/thefoodmedic/Facebook: https://www.facebook.com/thefoodmedic/Twitter: https://twitter.com/Thefoodmedic Explore More from The Food Medic Not Just A Period – New Book A groundbreaking guide to understanding your cycle, hormones, and health.Coming 22nd May 2025. Pre-order now: https://linktr.ee/notjustaperiod The Food Medic App Learn more: https://www.thefoodmedic.co.uk/about-the-food-medic-hub Weekly Newsletter Subscribe here: https://view.flodesk.com/pages/62b5a28d76b1bf772c403012 Get in Touch For inquiries or collaborations: General: [e-mail] Partnerships: [e-mail] Learn more about your ad choices. Visit podcastchoices.com/adchoices

So let's talk about fasted exercise and why I'm not a big fan of it in women. The reason why I don't love it and I don't think it's beneficial for women is that it can impact your menstrual cycles making them irregular. If this has happened to you I would rethink what healthy looks like because a good indicator of health is that your cycle is coming every month. Now I don't know about you but I definitely feel like I've experienced this in the past. Maybe with friends, with colleagues, with roommates, with sisters, you find that your period arrives at the same time. And the big million dollar question is, hello everyone, and welcome back to the Food Medic podcast. I'm Dr. Hazel Wallace, a women's health nutritionist and former NHS doctor, and I'm back for a special women's health

series of the FoodMedic podcast. In this mini series, we're diving into all things women's health, from expert insights and myth-busting chats to mini Ask Dr Hazel episodes, where I answer questions submitted by you. Expect accessible, evidence-backed tips to help you feel empowered, not held back by your menstrual cycle and more. If you're enjoying these conversations and want to go beyond just understanding your hormones and your menstrual cycle and actually learn how to work with them, my latest book, Not Just a Period, is available. It's a practical science-backed roadmap that helps you align your cycle in every area of your life,

from nutrition and mood, to body image, skin, hair and more. If you're ready to feel more in tune with your body and supported by your hormones, rather than confused by them, I'd love for you to check it out. You might notice a QR code floating around if you're watching the video, free to scan, or if you're listening to the audio version You can find the link at the bottom of the episode show notes Hi, Hazel. Love the pod. I just have a question for you Is it true that our period sync with people we spend time with like our friends or family?

Now I don't know about you, but I definitely feel like I've experienced this in the past. Maybe with friends, with colleagues, with roommates, with sisters, you find that your period arrives at the same time. And the big million dollar question is, is this just luck or is there something happening on a deeper level? Now, this effect is called the McClintock effect. And it comes from a study in the 1970s by a researcher called Martha McClintock.

And she observed that the menstrual cycles of college roommates started to sync up and align. And so they were coming around the same time. And since then, other research hasn't really been able to replicate those same results. And we're essentially at a point in the research where the belief is this is more down to odds than essentially some underlying hormonal mechanism.

And I know that when I answer this question and I say that it's a bit of a myth as opposed to a fact, a lot of women really don't like to hear that. And I get it because it's a really nice idea that we have this kind of female spiritual connection that our cycles are syncing up. And maybe it is there, but the research isn't showing that. And it looks like it's just luck because when you think about it, your cycle doesn't arrive on the same day every month. It will shift a little bit.

And if you're spending a lot of time with someone, it's likely that your cycles will end up arriving around the same time. So I know that's maybe not the answer you wanted to hear. And maybe you want to believe that I'm wrong and that cycles do sync with women in your life. But I'm just answering the question, what the evidence that I have and what we know. So thank you for sending it in. Hi, Hazel. I am such a big fan of your content and your podcast. Thank you so much. And I have a question for you. Is fasted exercise bad for your menstrual cycle?

Thank you so much for your question. So let's talk about fasted exercise and why I'm not a big fan of it in women. Now, if you've been following me on social media. We hope you're enjoying your Air Canada flight. Rocky's Vacation, here we come. Whoa, is this economy? Free beer, wine, and snacks. Sweet! Fast free Wi-Fi means I can make dinner reservations before we land. And with live TV, I'm not missing the game. It's kind of like I'm already on vacation.

Nice. On behalf of Air Canada, nice travels. Wi-Fi available to airplane members on equip flights sponsored by Bell Conditions Apply, seercanada.com. For a while, or maybe you've read my book, Not Just a Period, you will know why I am not a big fan of it. So essentially, fasted exercise is where we are exercising without having any food. And now a lot of people do this for convenience.

Some people do it for maybe potential benefits that they've heard about, or potentially they're trying to shift back their eating window so that they can have more food later in the day. Whatever the reason is, the reason why I don't love it and I don't think it's beneficial for women is that it can impact your menstrual cycles, making them irregular. And if you are someone who's doing a lot of exercise anyway, you could put yourself at risk of losing your period. Now, why is this? So I've talked about before in the podcast, but also I go into much more detail in the book that when we are in a calorie deficit, especially for extended periods of

time, we can lose our cycles because we put ourselves into a state of low energy availability. And essentially our body prioritizes things like our heart beating and our lungs breathing instead of regular menstrual cycles. And so if this has happened to you and maybe you have just started training for a marathon, for example, or you just started a new diet, I would rethink what healthy looks like because a good indicator of health is that your cycle is coming every month. When you are fasting, especially in fasted exercise, think about what that looks like. So you've been asleep all night, so you fasted all night, you wake up and you exercise.

So you put yourself even further into a deficit. Now you may make that up later in the day. And so maybe you will eat all your calories just a little bit later. But because you've put yourself into a situation which is known as within-day deficits, and this could happen if you also skip meals, you're going large chunks of the day where you're not consuming enough calories. And our bodies are very temperamental, a part of our brain called the hypothalamus, which is involved in all of these hormonal processes is very temperamental and it doesn't like those big gaps in energy. And so you might be someone who has been doing this for years and it's actually not harmed your cycle and your

cycle comes every month and you're very healthy. But if you're someone who is doing this and you're noticing changes in your cycle, I would stop doing it. I also don't think there's really any benefits to fasted exercise beyond maybe convenience. Because I know some people are waking up at 5am and no one wants to have to chow down a bowl of porridge at that time. If that's you, try just have a small carbohydrate-based snack because carbs are the source of energy that you're going to be using. So something like a banana, rice cakes, and some honey, a slice of toast, a slice of fruit loaf, something small that is just going to help take you out of that deficit and then

you can have your full breakfast later on. So I would just think about how you can have something small if you are exercising super early. Now, if you're only doing low impact exercise, like maybe it's a gentle yoga class or you do a morning walk with your dog, you don't need to worry about this. But if you're going for runs, high intensity exercise, high rocks classes, I really think you're better doing them fueled. An interesting study looked at this where they had a group of athletes and they had

the same energy intake, so same calorie intake across the day, but the group that had bigger within-day deficits actually had more, they were more likely to have irregular cycles. So it's important to just think about that. Like I've said, if you are someone who has found that your cycles disappeared in the past or it becomes irregular when you do increase your exercise or if you do try regimes like fasting or different nutrition protocols. So try it if you will, but it's not my favorite thing to do, especially in women. Thank you for your question. Hi, Hazel. So in the summer last year, I fell victim to the current social media trend of

pill bashing and decided to come off of my hormonal contraceptive pill that I'd been on for nearly 10 years to help with PCOS symptoms. So I guess my question to you is can you really heal PCOS holistically? Is the pill really that bad? I mean I'm thinking about going back on it because life was a lot less stressful when I was on it, let's put it that way. But yeah I just wanted to know your opinion on the whole holistic versus pill debate that is everywhere on social media. Thank you so much for your question and also for just sharing your own experience. As someone

who also has PCOS and works with women who have PCOS, I really feel you. And I feel your frustration as well. I think the whole conversation around the pill has maybe gotten a little bit out of hand on social media. I've even written a whole section in the book, in my new book, Not Just Period, on the pill and fear mongering around it and the conversation that's happening on social media. So I think there is a lot of fear mongering.

Now I think this conversation is really nuanced and for some women PCOS or not the pill can be transformative. It can be incredibly helpful for things that you've mentioned like acne and hair thinning and irregular cycles and painful periods. But it doesn't cure PCOS. Now it's prescribed in some situations in some women who have PCOS for various reasons, especially for some women who are having symptoms that they're unable to get a handle of. It also helps keep the wound lining nice and thin.

And if you're not having many menstrual cycles, that's something that's really important. But as I've said, it's not a cure. And I hear women's anger when it comes to doctors prescribing the pill as a band-aid solution when it doesn't solve the problem. And I would agree. But I think it doesn't have to be either or, or this and that. I think they can work together.

Now that's not me saying that every woman with PCOS needs to be on the pill. I think it's super individual and a conversation you need to have with your doctor. But it sounds like our listener is maybe making up that decision for herself. Now let's talk about the kind of second side of that question, which is, can you heal PCOS holistically? Now I am a women's health nutritionist and I would say 90% of my practice is PCOS. And as I've said, I've got PCOS myself and I've seen nutrition and lifestyle interventions be absolutely transformative for women with PCOS myself, and I've seen nutrition and lifestyle interventions be absolutely transformative

for women with PCOS. So when we think about it, 80% of women with PCOS have insulin resistance, and that is a big driver of PCOS symptoms. And through nutrition and lifestyle, we can help improve insulin resistance and therefore improve PCOS symptoms. Now there's a few pillars when it comes to what we can do within our lifestyle for PCOS and it's amazing that you're seeing a nutritionist and even better if she has experience in this area or he. What I would say is nutrition is kind of the big pillar that we want to focus on.

And it's not about following one specific diet. There's no superior diet when it comes to PCOS. And you do not need to cut carbs before someone else tells you to. Because when we pool all the research together and we look at different levels of carbohydrates in the diet for women with PCOS, low carbohydrate diets, so super low carb like keto, doesn't seem to be superior to moderate carb intake. So what most people are consuming in their day to day. So I think it's not something that you need to cut out and actually carbohydrates have

some benefits to them. There are primary source of energy, there's a lot of fiber in carbohydrates, they've B vitamins and other vitamins and minerals as well. So I'm a big advocate of keeping them in the diet. But what are the types of carbohydrates that we're consuming? We want to think about going for a high fiber complex carbohydrates. So our things like our brown rice, our whole wheat pastas, our whole grain breads, and pairing them with healthy fats and proteins so we can help manage that glucose response.

And I know I've talked about this in another episode. And essentially that's the really core key component when it comes to your nutrition. We want to follow a low glycemic diet. And this doesn't mean that you can't ever have a sugary slice of cake, but what are we doing 80% of the time? And it's thinking about that. Outside of that, there are some supplements that are evidence backed and can be helpful. I do think it's super individual, but I cover them in the book. At the end of the book, not just a period, there's an appendix on various different women's

health conditions. And I talk a little bit about what you can do for PCOS in terms of nutrition and supplementation there. But the other thing to think about is, are you moving your body? Are you doing strength training? I always say that muscle is a glycosponge, so we want to build lean muscle mass because that will really help with your symptoms as well. And think about what you're doing in terms of your sleep and your stress management.

Sleep problems are actually higher in women with PCOS. We want to make sure that we're getting enough and good quality sleep. Outside of that, we want to make sure that we're managing our stress and it's almost impossible to avoid stress in our day-to-day life. And a little bit of stress isn't bad for us, but a lot of stress is bad for us. So we want to think about how we can add pockets of stress management into our day. And maybe that's before you start work, you do a morning walk, maybe you do no social media first thing in the morning, maybe you do a yoga class twice a week, thinking about how you can

really bring down that stress response in a day-to-day way. That would be my best advice, but I need you to know that it is possible to improve your symptoms of PCOS. I'm really cautious to use the word cure, but you can get to a place where you aren't experiencing the symptoms of PCOS and maybe it's something that you're just managing. So I hope that gives you a wee bit of reassurance. I would say go back and speak to your doctor if you're considering going back on the pill and also keep working with your nutritionist and keep going.

A lot of the work when it comes to PCOS is silent work, but I see you. Thank you for your question. Before we leave each other, I would love if you could just take a moment to rate the podcast, leave a review or share it with a friend or a loved one that you think would learn a lot from this episode. If today's conversation resonated, my book, Not Just a Period is available and it's packed with practical advice to help you understand your hormones, manage tricky periods and work with your cycle for better energy, mood and overall health. You can grab a copy now through the link in the show notes or via the QR code

on your screen. I hope you all have a great week and thank you so much for listening. Hi there. I wanted to tell you about a podcast that I think every single one of you will benefit from. It's called Therapy Works and it's hosted by me, Julia Samuel. I'm a bestselling author and psychotherapist. I invite you into my therapy room where I speak to either a known or unknown guest. Topics range from the difficulties of divorce, a life-changing illness, to the struggles of motherhood. Search Therapy Works now, wherever you get your podcasts, and subscribe to make sure you never miss an episode.