For many women weight gain, brain fog, and energy crashes creep into their daily lives in their 40’s. Their diet hasn’t changed dramatically, exercise is about the same, and labs are often “normal”. This can be confusing and frustrating and is a pretty common symptom of perimenopause. Often the underlying issue is insulin resistance. So it’s natural to ask, “why do I suddenly have insulin resistance now that I’m in perimenopause?”
Why Do Women Experience Insulin Resistance in Perimenopause
Great question. The answer is a little complex, but we’ll get there.
Basically, during perimenopause, fluctuating estrogen and progesterone, lower SHBG, rising cortisol, and sleep disruption all contribute to insulin resistance.
These changes can cause weight gain, fatigue, and brain fog, sometimes before lab values become abnormal.
First, what is insulin resistance?
Insulin resistance occurs when the body’s cells don’t respond well, or respond sluggishly, to insulin, requiring higher and higher amounts of insulin to move glucose from the bloodstream into tissues. The primary tissues involved are muscle, liver, and fat.
If you think of insulin as the key needed to unlock the cells, in insulin resistance those locks become rusty. The key still works, but it takes more and more insulin to unlock the cells.
Over time, this chronic increase in insulin can contribute to weight gain, inflammation, and metabolic dysfunction, even when blood sugar levels are normal on labs.
The ups and downs of estrogen and progesterone in perimenopause play a major role in this rising insulin demand. The combination of declining estrogen levels and decreased sex hormone binding globulin, SHBG (a transport molecule for estrogen and testosterone, like a bus, that also regulates how much of those hormones are available to tissues) lead to higher levels of available testosterone. This hormonal shift promotes increased fat around organs, known as visceral fat.
Visceral fat is different from the fat just under your skin.
Fat around the organs acts like an endocrine organ itself, releasing inflammatory signals that interfere with insulin’s ability to work properly. This inflammation worsens insulin resistance, which then promotes even more visceral fat storage creating a frustrating cycle.
Declining estrogen can interfere with how the body manages blood sugar.
Estrogen helps the pancreas release insulin and helps the muscles effectively use that insulin. When estrogen levels fall or fluctuate, that system doesn’t work as smoothly, making glucose control more difficult.
Erratic progesterone also appears to worsen insulin resistance during perimenopause.
Progesterone inhibits several steps in moving glucose into the cells, so blood sugar stays high longer after meals. At the same time, progesterone also signals the liver to release more glucose into the bloodstream, compounding the problem.
This typically happens when progesterone is high, so if estrogen is declining leaving progesterone high, then this insulin and blood sugar aggravation is possible. It’s important to note that progesterone isn’t bad, it’s just not balanced with estrogen while the hormones are fluctuating so wildly.
Cortisol also plays a major role here.
Cortisol typically rises in perimenopause. That high cortisol can lead to insomnia and the night waking can lead to worsening insulin resistance by increasing blood sugar production and reducing insulin sensitivity the following day. This creates another cycle: hormonal shifts, poor sleep, and blood sugar dysregulation.
Signs of insulin resistance are post-meal crashes, central weight gain without changes in diet or lifestyle, and worsening PMS, anxiety, and brain fog.
There’s more to this story, but these are the broad strokes.
What this ultimately means is that visceral fat gain during perimenopause is a consequence of insulin resistance and hormonal chaos, not a lack of willpower or discipline.
While nutrition and movement still matter, aggressive dietary restriction and excessive cardio alone often fail to address the root causes of insulin resistance in this phase of life.
Supporting hormones, sleep, muscle mass, and stress physiology is just as important as what’s on the plate.
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Dr. Jennifer Potter, ND
Naturopathic Doctor San Jose
408-356-1364
Dr. Jennifer Potter, ND provides natural healthcare solutions for families and individuals, focusing on perimenopause/menopause, autoimmune conditions, fatigue, and immune support. She is deeply committed to her patient’s well being, prioritizes patient education and combines natural and conventional therapies to deliver personalized care. Outside of her practice, she enjoys time with her two kids, reading fiction, and crocheting.
Resources
Menopause: A Cardiometabolic Transition. The Lancet. Diabetes & Endocrinology. 2022. Nappi RE, Chedraui P, Lambrinoudaki I, Simoncini T.
Onset of the Climacteric Phase by the Mid-Forties Associated With Impaired Insulin Sensitivity: A Birth Cohort Study. Menopause. 2020. Savukoski SM, Suvanto ETJ, Auvinen JP, et al.
Progesterone Inhibits Glucose Uptake by Affecting Diverse Steps of Insulin Signaling in 3t3-L1 Adipocytes. American Journal of Physiology. Endocrinology and Metabolism. 2010. Wada T, Hori S, Sugiyama M, et al.
Longitudinal Study of Insulin Resistance and Sex Hormones Over the Menstrual Cycle: The BioCycle Study. The Journal of Clinical Endocrinology and Metabolism. 2010. Yeung EH, Zhang C, Mumford SL, et al.
