20: Reading Your Body: What a CGM Teaches You About Metabolic Health in Perimenopause

Hey, it’s Megan. Grab your coffee and let’s have a convo.

Why Your Blood Sugar Gets Harder to Manage in Perimenopause

Good morning and welcome back to Mornings with Megan. I want to start today with a question and I want you to actually answer it in your head. Well, I guess you can answer it out loud, but if you’re on the train, people might give you some looks. But hey, you do you this morning.

Have you ever been completely fine, totally on track with your day, and then out of nowhere — usually somewhere around 3pm, sometimes after dinner — you’re suddenly starving, irritable, foggy, and you need something sweet right now? Or maybe you wake up at 2am, heart pounding, a little sweaty, weirdly anxious, and you have no idea why?

That’s not a willpower problem. That’s not you failing at healthy eating. That is your blood sugar talking — and in perimenopause, that conversation gets a lot louder and a whole lot more confusing.

Today we’re covering continuous glucose monitoring — what it is, what it actually shows you, and why it’s one of the most useful tools I’ve found for understanding what’s happening in your body right now, in this stage of life. This falls squarely in the Fuel pillar of my Perimenopause Matrix — because how your body handles blood sugar underpins your energy, your cravings, your sleep, your mood, and your metabolic health for the long game.

The Hormone Connection You Were Never Told About

Here’s the piece most women are never told — and once you understand it, you cannot unsee it: the hormone shifts of perimenopause directly affect how your body handles blood sugar, and this starts earlier than most women expect.

Estrogen directly supports insulin sensitivity. So as estrogen begins to fluctuate, your cells become less responsive to insulin. The oatmeal that was fine at 38 might tank you at 44. That’s not a personal failure — that’s just physiology.

But estrogen isn’t the only player here. And if you’re in early perimenopause, progesterone is often where things start to unravel first. Progesterone begins to decline before estrogen does, and in the luteal phase — the week or two before your period — those drops can start getting pretty dramatic. Fluctuating progesterone in the luteal phase contributes to blood sugar instability, which is exactly where those intense pre-period cravings, unexpected weight gain, and PMS symptoms are coming from.

And here’s the part I really want to land for you: low progesterone also means disrupted sleep. Disrupted sleep drives cortisol up. And elevated cortisol drives insulin resistance. So if you are lying awake at 3am in the week before your period, your blood sugar the next day is paying the price — even if you ate perfectly.

Testosterone also plays a role. In women, higher free testosterone is associated with greater insulin resistance and metabolic instability — which is part of why PCOS has such a strong metabolic component. But testosterone levels also shift in perimenopause, and having levels that are out of range in either direction can affect your metabolic stability. It’s another reason why looking at your full hormone picture — not just one marker in isolation — matters so much.

There is now strong meta-analysis data showing that MHT — menopause hormone therapy — can significantly reduce insulin resistance in postmenopausal women. Which means getting your hormones into a stable, supportive range is not just about symptom relief. It has real metabolic implications. That is a conversation worth having with your doctor.

All of this is to say: if your blood sugar feels harder to manage than it used to, if the cravings feel different, if the same foods aren’t working the same way — you are not imagining it, and it’s not a personal failure. Your hormones changed. And this is exactly why we talk about the Fuel pillar of the Perimenopause Matrix — because what your body does with food cannot be separated from what your hormones are doing.

What Is a CGM and How Should You Actually Use One?

I’ve run a CGM before and spent years working on balancing blood sugar and decreasing my cravings. This took close to a decade to get managed — and even now, I still have moments where my blood sugar gets out of control. The point of a CGM — to me, outside of diabetes management — is a learning tool. It’s something you can use to understand what affects your blood sugar, and there are many different things that do.

I’ve been trying a new app that works with my CGM. There are several out there now that go beyond the basic monitoring software to actually parse your data, score your meals, and give you patterns over time. And using one has reinforced something I want to say upfront, because it underpins a lot of what we’re going to cover today: a carb is not a carb, is not a carb, is not a carb.

The basic CGM software asks you to log a food event and enter the number of carbs. That is an extraordinarily reductionist way to look at food — because a bowl of white rice eaten alone does not behave the same way in your body as it does in mine. And neither of those is the same as that rice eaten after two cups of vegetables and a steak. The fiber content, the meal context, your stress levels, your sleep the night before, your individual physiology — all of it matters. The number of carbs is just the beginning of the story, which is exactly why CGM data means very little without context, and why working with someone who can help you build that context — or at minimum keeping detailed notes alongside your data — makes all the difference.

One of the most valuable things a CGM can give you is a baseline — a picture of how your body responds to food, stress, sleep, and movement under normal conditions. And that baseline is what makes everything else useful.

I would not recommend wearing a CGM during a period of extreme stress — a divorce, a move, a newborn at home, a really difficult season at work. Not because the data isn’t interesting, but because for many people — myself included, and I’ve heard this from other practitioners and clients as well — the act of watching and tracking is itself a stressor. And as we’re about to talk about, stress raises blood sugar. So you’d be adding a variable to an already noisy picture. Get your baseline first, when life is relatively stable. Then, when a high-stress period hits, you can use the strategies you’ve already learned to take extra care of your metabolic health — without needing to be wired up to do it.

The CGM Is a Map, Not a Report Card

There’s also what I’m going to call “being watched” stress. Freddie asked me why I was being so competitive and I said, I’m not competitive. And he said, you have been trying to beat the CGM for the past week. And I thought — huh, he’s right. I don’t really want to beat the CGM, but I do want a perfect score, a gold star, and a pat on the head. First-born baggage. I’m working on it.

I spoke to a menopause doctor recently and she shared a similar insight — the stress of being watched and wanting to be perfect actually causes cortisol elevation and higher blood sugar readings. Both times I ran my CGM, I felt that same compulsion to watch, track, respond, and think about the data constantly.

And this connects directly to the Regulate pillar of the Perimenopause Matrix — your stress response and your blood sugar are deeply intertwined. Cortisol signals your liver to release glucose, so a stressful thought, a tense email, even the anxiety of watching your CGM too closely can actually raise your readings. This is why I want you to think of a CGM as a map, not a report card.

My CGM data runs higher than standard blood draws, but my overall metabolic metrics look good — so I’m not concerned about this little stress bump from being watched. I’m more interested in the patterns the CGM reveals. And that is exactly how I think CGMs should be used.

My Personal Trials: What I Learned From Oats, Rice, and My Own Body

I like the CGM to inform, not to judge or shame. I did a few trials I wanted to share with you, because every body is individual.

I really want to be an overnight oats person. In the past, oatmeal has not worked well for me, but there are documented benefits around LDL, resistant starch, and overall mortality. So I cooked steel cut oats in a crockpot, spiked them with protein powder, seeds, and berries, and then let them sit overnight — maxing out everything I know to make them less glycemic. I trialed them the next morning before going to the gym.

They gave me a big spike, and then the reactive drop went so low it set off an alarm during my workout. This is called reactive hypoglycemia — a sharp rise in blood sugar followed by a crash below normal. I knew what was happening and had even hypothesized it, so I wasn’t stressed. I didn’t get cravings. My stomach felt full, like there was still food in it. I did get sweaty — which, yes, you’d expect at the gym, but I’m not a sweater, and sweating is part of low blood sugar. I was still able to work out, my energy didn’t dip, I didn’t feel shaky — but I felt like if I were sprinting or doing intense cardio, I would have tired quickly.

I did a second trial a few days later with a quarter of the amount of oats in my chia seed pudding with protein powder, seeds, and berries. I wasn’t planning a workout because I wanted to see how I did while I’d normally have my chia seed pudding when I was working. My blood sugar went up so much that I did 60 seconds of jumping jacks, butt kicks, and air squats, followed by eight stair sprints to bring it back down. I still got a reactive crash and an emergency alert. So now I know — oats are not for me. If they’re in a dessert or something I really want, I need to do activity afterwards and I’ll probably still have a crash. Oats will not be a regular part of my life.

We are all individual, and this is why I love a CGM. I can tell you that steel cut oats have documented health benefits — but they may not be right for you. I have a similar reaction to rice, so I don’t eat it. I worked with a client who ate white rice and had no problems at all.

There are things you can do with grains like oats and rice — such as cooking them in bone broth or coconut milk — to reduce their glycemic impact. That’s something you can experiment with if you ever use a CGM.

Okay — real talk. If you just laughed at me doing jumping jacks in my kitchen to save my blood sugar, or if you immediately thought of someone in your life who needs to hear this — send them this episode. Seriously, just text it to them right now. We all know a woman who is exhausted, confused about her body, and has been told everything looks “normal.” This episode might be exactly what makes her feel seen. Forward it, share it, drop it in the group chat. The more women who have access to this information in perimenopause, the better. Okay, back to it.

It’s Not Just Food: Stress, Sleep, Movement, and Sex on a CGM

One of the other things the CGM tells you is how non-food events affect your blood sugar. If you get in a fight with someone, if you have a stressful work situation come up, when you work out, when you have sex — all of these things show up in your data.

Movement

Movement is one of the most powerful tools you have for managing your blood sugar — but it’s not one-size-fits-all, and your CGM will show you that clearly. Walking or moderate movement after a meal — just 10 minutes — helps your muscles use that circulating glucose and brings the spike down faster. I personally see a significant drop from walking and rucking.

But there’s some nuance here. Intense exercise that pushes up cortisol can actually raise your blood sugar, especially if you’re working out between meals when glucose is already low. Your body reads that intensity as a stress signal, releases cortisol and glucagon to free up energy for the work, and your liver dumps glucose into the bloodstream to fuel it. So you might see a rise at the start of a hard workout before things come back down. That’s not a bad sign — that is your body doing exactly what it’s supposed to do. The sweet spot for blood sugar management is moderate movement, especially after meals. That’s your Move pillar working directly in service of your Fuel pillar.

Sex

And while we’re talking about non-food events that show up in your data — let’s talk about sex. Yes, really. For me, sex after dinner before my blood sugar had fully recovered extended my recovery time and bumped up my levels just a little bit. Based on what we know about exercise physiology, sex likely falls into the moderate intensity category — enough effort to trigger some cortisol and get your heart rate up, which means your body may free up a little extra glucose to fuel it.

Newer encounters tend to come with more adrenaline, which is a cortisol driver. More established ones involve more oxytocin, which has a calming effect. So the response is generally going to be different depending on the situation — and I say that completely seriously. The NIH is not exactly lining up to fund CGM and sex research, so we’re extrapolating from exercise data here. But it’s worth knowing that if you see something unexpected in your overnight numbers, context matters. Don’t panic. Just note it.

Stress

Let me give you a real example of how much stress changes the picture. On a low stress day, I ate two and a half cups of potatoes after a steak, broccoli, and cauliflower — and my blood sugar reached only 130. Now compare that to a different day: a super stressful afternoon, and just three quarters of a cup of potato at dinner — and I hit 175.

Three quarters of a cup of potato with stress hit 40 points higher than two and a half cups without it. Let that land for a second. Then, after my blood sugar recovered from those potatoes, I had some Hippeas — those little chickpea puffs that are one of my favorite snacks. They doubled the blood sugar rise they had caused on the calm night. Same snack. Very different response. That is how much your stress response is affecting your blood sugar. The food is not the whole story.

Sleep

And then there’s sleep — specifically, waking up in the middle of the night. This is one of the most important things in this episode, especially if you’re waking up between 2 and 4am and can’t go back to sleep. This often happens because of low blood sugar. Your blood sugar drops during the night, your body releases cortisol and adrenaline to bring it back up — and those stress hormones are what wake you. You come to feeling anxious, maybe a little sweaty, heart pounding, with no idea why.

Now here’s where it gets really interesting in perimenopause: that 2am wake-up with sweating and anxiety? It might not be a hot flash. It might not be a vasomotor symptom at all. It could be a blood sugar crash — or it could be both, because low blood sugar triggers a cortisol response, and cortisol can trigger a hot flash. The two are completely connected, and they’re happening in the same body, at the same time, often in the same night. This is why we look at the whole picture. This lives in both the Fuel pillar and the Recharge pillar of the Perimenopause Matrix — because your sleep and your metabolic health are in constant conversation with each other.

And the CGM doesn’t lie about sleep quality either — it shows you exactly what your blood sugar is doing overnight. On the nights I slept straight through, my blood sugar was rock solid stable. The app I was using actually flagged it — which, yes, I will absolutely take that pat on the head. When I woke up briefly and fell back asleep, there was a little more variability — about a 10 point range — but nothing dramatic. When I was waking up for longer stretches, the fluctuations were wider, about 16 points, and they looked different too — a lot more like jagged ups and downs rather than the slow, gentle undulations of a good night’s sleep. Your CGM is not just a food tracker. It is a sleep quality monitor.

The Morning After

Here’s what that elevated dinner blood sugar meant the next morning: I was hungrier. Not ravenous, but noticeably more hungry than on mornings after a stable night. I knew what was happening so I didn’t overeat — but think about what that looks like if you don’t have that context. You wake up hungrier, you eat more than you planned, your blood sugar spikes earlier in the day, you’re chasing energy and cravings by 2pm — and you have no idea that it started the night before at dinner. Now imagine that’s happening every single night. That’s not a willpower problem. That’s a blood sugar pattern that nobody told you about.

Compounded Events: Why Your CGM Data Can Look Worse Than It Is

One of the things that can be really confusing with CGM data is compounded events — eating and then working out, having sex and then a snack, a stressful situation right before lunch. How do you tease these apart?

You can try to test things independently, which gives you a cleaner answer — but that’s not always practical. We are not lab rats who can wait until our blood sugar returns to baseline before reading a stressful email or going for a walk.

Here’s a perfect example from my own data. I had a meal that was scored very low in the app I was using: eggs, ground meat, bacon, peppers, half a kiwi, green beans, and a few leftover potato wedges — about 21 grams of carbs total, which is quite low. But I was working between clients, and I had a hot chocolate with protein powder about 30 minutes after the meal — and then another one about an hour and a half later. No spike from either of them, but my blood sugar took three hours to fully recover. On paper, that looks like a terrible meal. It wasn’t. The meal was completely fine. What happened was two separate food events compounded my recovery window — each one gave my body something new to process before it had finished with the last.

There’s actually something useful to note here: having something sweet right after a meal — like that hot chocolate — can work in your favor, because the meal itself acts as a buffer and slows the sugar hit. The problem wasn’t the hot chocolate. The problem was the timing — spread out over two hours instead of right after eating. In an ideal world I would have had both right after the meal. But this is real life, and real life doesn’t always cooperate.

The bigger lesson is this: the fewer separate food events you have throughout the day, the cleaner your blood sugar data — and your metabolic health — will be. Not because you can never have a hot chocolate between clients, but because when that’s your baseline, the occasional complicated day doesn’t need to move the needle that much. It’s when compounding events are happening every single day that it starts to accumulate. This is also exactly why working with someone to look at your full picture — your food, your stress, your sleep, and your timing — is so much more useful than staring at your CGM data alone trying to figure out what went wrong.

This is exactly why CGM data should never be looked at in isolation.

The Labs That Make Your CGM Data Make Sense

Getting your fasting insulin, fasting glucose, hemoglobin A1c, and triglycerides is really important alongside your CGM data. If you have a doctor who leans toward precision or functional medicine, ask for an hs-CRP and uric acid as well. Together, these give you the most complete picture of your metabolic health.

Hemoglobin A1c is used to diagnose insulin resistance, pre-diabetes, and diabetes. It’s generally a reasonable marker — but as we covered in our lab episode, it should never be used in isolation, because there is meaningful individual variability.

Hemoglobin A1c looks at your average blood sugar over the past three months. It does this by measuring how many glucose molecules bind to the hemoglobin in your red blood cells — think of it like a sticky protein traveling through your bloodstream, gradually picking up glucose molecules along the way. The longer your red blood cells are in circulation, the more glucose they accumulate.

Here’s where it gets interesting: most research sets the average red blood cell lifespan at around 120 days, but there’s a range that can go anywhere from 70 to 140 days — and that’s a significant difference. If your red blood cells turn over at 90 days but mine turn over at 120, your hemoglobin A1c may look lower than mine simply because your cells have had less time floating around to pick up glucose. Mine might read higher — not because my blood sugar is worse, but because my red blood cells live longer.

I have a client who has been very worried about insulin resistance. Her doctor had her change her diet and eating habits and wear a CGM. Her father also had a high hemoglobin A1c his entire life but was never diagnosed with any chronic conditions. She was able to bring her hemoglobin A1c down about 0.3 points — which is solid. But there is a lot of stress and worry around this label of pre-diabetes at 5.7. The rest of her labs don’t suggest insulin resistance. I reviewed her CGM data and it also doesn’t suggest insulin resistance. Her doctor is going to run a fasting insulin and a few additional tests to confirm — but this is exactly why you should never look at any of these markers in isolation. If she has red blood cells that live a long time, that could explain everything. Without taking the time to look at the whole picture, she could be walking around stressed about a pre-diabetes label when she is actually metabolically healthy.

What This All Means for You

So let me bring this back to you and what I want you to take away from today.

Everything we covered — blood sugar, CGM data, hemoglobin A1c, reactive hypoglycemia, that 2am wake-up — this all lives in the Fuel pillar of the Perimenopause Matrix. Fuel is about how your body actually uses energy: how you eat, how your metabolism responds, how your blood sugar patterns affect everything from your cravings to your energy to your sleep. And the Fuel pillar connects directly to Regulate — because your stress hormones and your blood sugar are in constant communication — and to Recharge, because your metabolic health and your sleep quality are inseparable. And as we talked about today, your Move pillar is one of the most immediate levers you have. A 10 minute walk after dinner isn’t just good for your mood. It is metabolic medicine.

You don’t need a CGM to start working on this. But if you’ve ever felt like your body is sending you signals you can’t decode, a CGM is one of the most illuminating tools I know.

Your Move This Week

Pick one meal where you regularly feel a crash coming on — the afternoon slump, the 3pm cravings, the post-lunch fog. Note what you ate, when you ate it, and how you felt 90 minutes later. You don’t need a CGM to start noticing patterns. Your body is already giving you data — we’re just going to start reading it together.

Work With Megan

If this episode made you want to understand your own metabolic picture — not just the CGM, but your fasting insulin, your hemoglobin A1c in context, your full metabolic panel — that’s exactly what we do in the Matrix Lab Review. You send me your labs and I walk you through what they mean for you, specifically, in perimenopause. The link is in the show notes.

Not sure where to start? The Perimenopause Symptom Decoder helps you identify which pillars of your Perimenopause Matrix need the most attention right now — so you can stop guessing and start getting answers. Link in the show notes.

Can you do me a favor? If this was helpful, share it with one person who might need to hear it today. Our bodies didn’t come with a user manual, and this perimenopause thing can feel confusing and lonely — but you’re not alone, you’re not crazy, and you’re definitely not broken. And maybe someone in your life needs that reminder too. Let’s spread the word and be kind to each other and ourselves.

Now the legal bit: I’m a nutritionist, but I’m not your nutritionist. This podcast is for information and education only. No client relationship was formed. Always seek medical advice when necessary. I’ll see you next Wednesday morning.