I’m Healthy, Active…And Prediabetic—But Only In My Luteal Phase

How I used a continuous glucose monitor to identify cyclical insulin resistance over the course of 3 months and find balance without lifelong medication.

In a previous blog, I detailed my progression from gestational to prediabetes. I described the limited support I received from my primary care physician during the first appointment to discuss a type 2 diabetes prevention plan and how I chose to challenge the prescribed course of action when it didn't feel right for me.

She was eager to write a prescription and send me on my way.

I was eager to move the needle on my own without lifelong medication. 

We met in the middle with a plan to implement dietary and lifestyle changes for a period of 3 months and then retest my HbA1c.

The truth is, if you are a woman, your blood sugar matters. There are practical ways to support your metabolism and overall health by addressing insulin resistance and they’re not as taxing as you might think. No swearing off carbs and no need to devote more time and energy to exercise, I promise.

Short on time? Here are the key takeaways:

If you are a menstruating woman, blood sugar matters. Erratic glucose spikes—even within a normal range—can contribute to mood swings, brain fog, fatigue, and PMS.

After experiencing symptoms of elevated blood sugar, I used a continuous glucose monitor to identify luteal phase insulin resistance where my average readings exceeded normal thresholds in the last two weeks of my cycle.

Moderate-intensity exercise was problematic in my luteal phase and produced considerable glucose spikes that took longer to return to normal.

Carbohydrates produced a considerably higher glucose spike when consumed alone than when paired with protein and fat.

A little bit of low-intensity movement after meals had a stabilizing effect on blood glucose and kept it from spiking in the postprandial period.

As a healthy and active woman with a healthy weight, my battle with blood sugar stems not from lifestyle factors, but from genetics, insufficient protein intake, and hormone-related insulin resistance.

• Medical Disclaimer

  The guidance included in this post is intended for active women participating in some form of regular resistance training and exercise.

  Information in this post and on this web site is provided for informational purposes only. The information is a result of practice experience and research by the author. This information is not intended as a substitute for the advice provided by your physician or other healthcare professional or any information contained on or in any product label or packaging. Do not use the information on this web site for diagnosing or treating a health problem or disease, or prescribing medication or other treatment. Information and statements regarding dietary supplements have not been evaluated by the Food and Drug Administration and are not intended to diagnose, treat, cure, or prevent any disease. Always speak with your physician or another healthcare professional before taking any medication or nutritional, herbal, or homeopathic supplement, or using any treatment for a health problem.

Why 3 Months?

An HbA1c test measures the amount of glucose coating the hemoglobin protein in red blood cells. Since red blood cells live for roughly three months long and the coating remains for the lifespan of the cell, this marker provides a good representation of your average blood glucose over a three-month period. 

There’s a divine rhythm to this three-month cycle. 

It’s the length of a season in nature and it’s woven into other systems in the female body like egg maturation and the return to baseline hormone levels after giving birth. 

It makes sense that we would see a similar three-month timeline for interventions to take effect when balancing hormones and stabilizing blood glucose because they work in tandem within the endocrine system. 

Data Gathering With A Continuous Glucose Monitor

Daily Insights 

Reluctant to reenter the world of finger pricks and printed glucose charts, I enlisted the support of a continuous glucose monitor (CGM) to help me understand my body’s patterns a little better. 

Over the next 3 months, I opted for intuitive eating in lieu of daily diet tracking and simply paid attention to the impact of food and lifestyle choices on my blood glucose levels. It felt more freeing to become more in tune with my body versus obsessing over carbs and track everything I put into my mouth. 

Most of the following takeaways from my data collection made sense with a kicker at the end.

• I learned which carbohydrates produced considerable spikes and which came on more slowly. For example, I can tolerate berries and dairy, but sweet potatoes and grains require higher protein pairings to stave off a spike. 

• Not all sweeteners are created equal. Honey sends my glucose soaring, but maple and date syrups produce a more gradual climb. 

• Love ‘em or hate ‘em, sweet substitutes have become a staple in my morning beverage routine. Stevia and monk fruit give me the flavor I love without the impact on blood glucose. 

• I found proof in the numbers that naked carbs don’t work for my body…gone are the days of munching on salty snacks between meals or enjoying an apple on the go. 

• Not surprisingly, a little bit of movement after a meal goes a long way and helps my body metabolize carbohydrates. Here’s my favorite post-meal movement practice when I can get away for a walk outside: 15-Min LISS Workout to Regulate Blood Sugar and Improve Luteal Phase Insulin Sensitivity

• Stress has a significant impact on my blood glucose levels. Be it real, perceived, or self-inflicted, when I feel stressed, it shows. On more than one occasion, during particularly challenging times e.g. big feelings from two toddlers, illness, and lack of sleep, my glucose alarm sounded alerting me to a hyperglycemic event of > 240 mg/dL. These often happened outside my post-meal windows and it was clear that internal stress was the culprit. 

Ultimately, using a CGM provided valuable insights that now inform my daily food and exercise choices. It was a fascinating experiment and I feel more empowered with what I learned about my body.

More Cyclical Clues 

While using a CGM to track three full menstrual cycles, a few additional phasic patterns emerged:

• Fasting glucose readings were significantly higher in my luteal phase (between 120-140 mg/dL) than in my follicular phase (between 80-100 mg/dL).

• Similarly, postprandial readings (2 hours after a meal) were significantly higher in my luteal phase (between 140-170 mg/dL) and took longer to normalize than in my follicular phase (between 120-140 mg/dL).

• I tend to have erratic blood glucose levels for a day or two during ovulation where postprandial values regularly exceed 200 mg/dL and stay elevated for a longer period of time. 

• HIIT workouts produce a considerable spike between 180–200 mg/dL followed by a sharp decline to normal in my follicular phase.

• A similar period of elevated blood glucose occurs in my luteal phase (even with moderate exertion), but it lasts for a few hours after stopping exercise. 

After 3 months of data collection, it appears that I am indeed prediabetic, but only in my luteal phase! 

Why Me? And Why Now?

Honestly, I still feel a bit in denial that I’m even writing this blog post!. I am young, healthy, and active…where did I go wrong? 

The truth is, I don’t have a great answer, but my intuition and research tells me it is a combination of the following:

• A genetic predisposition to insulin resistance. My mom and I have the same HbA1c and it wasn’t until my experience with gestational diabetes that we really started talking about the prevalence of metabolic disease in our family. It’s there and it makes a difference.

• Habitual over consumption of carbohydrates. I am a child of the 80’s and I was just coming into adolescence during the widespread villainization of fat from food. As a result, my early efforts to manage weight during college were centered around low fat foods that often contained obscene amounts of carbohydrates. 

• Insufficient protein. As a vegetarian for many years, and before having any experiential wisdom to rely on, my meals were often lacking in protein. I opted for vegetarian-friendly foods that packed a higher carbohydrate content and as a result, I often didn’t have the full macronutrient spectrum to support healthy blood sugar. 

• Hormone-related insulin resistance. While the conditions above have been with me for over a decade, I wasn’t given a reason to pay attention to blood sugar until my system was flooded with hormones during pregnancy. My kids helped me connect the dots between high hormone levels and insulin resistance and I’m grateful for these lessons.   

The truth is, if you are a woman, your blood sugar matters. 

There are practical ways to support your metabolism and overall health by addressing insulin resistance and they’re not as taxing as you might think. No swearing off carbs and no need to devote more time and energy to exercise, I promise.

In the next blog post, you’ll find out how I am managing prediabetes and how I was able to get my blood sugar back to normal levels with both a daily and phase-specific protocol.