Insulin Sensitivity and Long-Term Health
- Elizabeth Priest
- Jun 7
- 5 min read
The hormone insulin is a core component of metabolic health—how your body makes and uses energy. While insulin is best known for helping shuttle glucose (blood sugar) into cells, it plays a critical role in nearly every system of the body. Because of this, insulin dysfunction, particularly insulin resistance, is a root cause or contributing factor to chronic conditions like heart disease, type 2 diabetes, PCOS, and even Alzheimer's disease.
What Is Insulin and How Does It Work?
Insulin is a hormone produced by the pancreas, specifically by specialized β-cells (beta cells). It acts as a chemical messenger that travels through the bloodstream, signaling cells to absorb glucose and use it for energy or store it for later.
When you eat, your body breaks down carbohydrates into glucose, which enters the bloodstream. In response, insulin is released to help shuttle this glucose into your cells. Glucose is either used immediately for energy or stored as glycogen in the liver and muscles. Once glycogen stores are full, excess glucose is converted into triglycerides and stored in fat cells.
Fun fact: Glycogen stored in muscle tissue can only be used by that specific muscle. It can't be shared or used elsewhere in the body, which is one reason regular movement and exercise are so important.
What Is Insulin Resistance?
Insulin resistance occurs when cells become less responsive to insulin's signals. As a result, the body compensates by producing more insulin to manage blood glucose levels. Over time, this leads to elevated blood sugar and insulin levels. If left unaddressed, this can progress to prediabetes and eventually type 2 diabetes, when the pancreas becomes unable to keep up with insulin production.
Why Insulin Should Be Tested Early
Insulin is often overlooked in conventional medical testing, but it's one of the earliest indicators of metabolic dysfunction. Elevated insulin can occur years before fasting glucose or HbA1c levels show abnormal readings. That means someone can be insulin resistant even with "normal" blood sugar labs. Regular assessment of fasting insulin is essential for early detection and prevention.
Signs and Symptoms to Watch For
Insulin resistance can present with subtle but persistent symptoms, including:
Difficulty waking in the morning
Afternoon headaches
Feeling shaky or lightheaded if meals are delayed
Increased hunger and thirst
Frequent urination
Sugar and carb cravings
Mood swings and irritability
Fatigue, especially after meals
Difficulty sleeping or nightmares
Weight gain around the midsection
Darkened patches of skin around the neck or armpits
Many of these symptoms are related to the body's impaired ability to regulate glucose and insulin, which can create a cascade of hormonal and metabolic stress.
Important note: Insulin resistance isn't just a problem for those who are overweight. Even lean individuals can develop insulin resistance due to chronic stress, sleep deprivation, gut dysfunction, or inflammation.
Root Causes of Insulin Resistance
Insulin resistance develops over time and is influenced by several lifestyle and environmental factors:
A diet high in refined carbohydrates and sugars
Sedentary lifestyle
Excess visceral fat
Gut dysbiosis and poor digestion
Chronic inflammation
High toxic burden (environmental and metabolic)
Chronic or acute stress
Hormonal imbalances
Genetic predisposition
Insulin resistance is highly reversible when caught early and addressed with a functional medicine approach.
Chronic Conditions Linked to Insulin Resistance
1. Type 2 Diabetes
Chronic insulin resistance places stress on the pancreas to produce more insulin. Over time, the pancreas may fail to keep up, leading to elevated blood glucose levels and a diagnosis of type 2 diabetes.
2. Cardiovascular Disease
Insulin resistance contributes to high blood pressure, poor cholesterol ratios, and systemic inflammation—all key risk factors for heart disease and stroke.
3. Alzheimer's & Neurodegeneration
Sometimes referred to as "type 3 diabetes," Alzheimer's disease is increasingly linked to impaired insulin signaling and glucose metabolism in the brain.
4. Women's Health: PCOS, Hormone Shifts, and Weight Loss Resistance
Insulin resistance plays a significant role in PCOS by increasing androgen production, which disrupts ovulation, causes acne, and contributes to weight gain. It also becomes more common during perimenopause and menopause, when hormonal shifts can make blood sugar regulation more difficult—even for women who eat well and exercise.
5. Metabolic Syndrome
Also known as Syndrome X, metabolic syndrome is a cluster of conditions driven primarily by insulin resistance. These include:
Elevated fasting glucose or HbA1c
High triglycerides and cholesterol
Low HDL ("good") cholesterol
High blood pressure
Abdominal obesity
Poor diet quality
Lack of physical activity
Insulin resistance activates the HPA axis and increases cortisol production, worsening the issue. Breaking the cycle requires a root-cause approach.
Shockingly, research shows that only about 7% of American adults are considered metabolically healthy—meaning they have optimal levels of blood pressure, blood sugar, cholesterol, weight, and cardiovascular health without the need for medication. This staggering statistic highlights just how widespread insulin resistance and poor metabolic health have become—and why proactive testing and personalized lifestyle strategies are more important than ever.
6. Obesity
Chronically high insulin levels promote fat storage, particularly in the abdominal region, while simultaneously making it harder for the body to burn fat for energy.
7. Metabolic-Associated Fatty Liver Disease (MAFLD)
Excess insulin and glucose promote fat buildup in the liver, leading to inflammation, fibrosis, and potentially cirrhosis. MAFLD is strongly linked to insulin resistance, even in people without obesity.
Functional Biomarkers to Track
To get a complete picture of your metabolic health, consider testing the following biomarkers:
Fasting glucose
HbA1c
Fasting insulin
IGF-1
Leptin
Total cholesterol, HDL, LDL, triglycerides
LDL particle size & number
Lipoprotein (a)
hs-CRP
Homocysteine
Cortisol (serum or saliva)
Work with a functionally minded practitioner who can interpret this data through a systems-based lens. Self-guided biohacking can miss the root cause and delay meaningful progress.
Helpful tools: A Continuous Glucose Monitor (CGM) or a Keto Mojo device can offer real-time insight into how your body responds to food, stress, and lifestyle choices. These tools provide valuable feedback to help you personalize your approach and improve metabolic flexibility.
How to Improve Insulin Sensitivity
Diet
Nutrition is foundational. A diet rooted in Paleo principles—whole, unprocessed foods, quality protein, healthy fats, and fiber-rich vegetables—can support blood sugar balance. Some individuals also benefit from a ketogenic macronutrient profile to improve metabolic flexibility and reduce insulin demand.
Key strategies:
Prioritize low-glycemic foods
Increase lean protein for satiety and muscle support
Boost soluble fiber for gut and glucose regulation
Practice time-restricted eating (10–12 hour window)
Movement & Exercise
Exercise improves insulin sensitivity by helping your muscles absorb glucose without insulin. Incorporate:
Zone 2 cardio: 60–70% of max heart rate for 30+ minutes
Strength training: Build and activate muscle tissue
Movement breaks: 2–3 minutes every 45 minutes to reduce post-meal glucose spikes
Sleep
Poor sleep disrupts hormone balance and increases insulin resistance. Just one extra hour per night can improve glucose regulation, especially in women.
Supplements & Peptides
Targeted supplements and peptides can amplify your results:
BerbElite (Mara Labs): High-potency berberine for insulin regulation
Glysen (Apex Energetics): Supports liver and metabolic function
Metabolic Daily & GLP-1 Probiotic Pro (Pendulum): Probiotics to improve gut-driven glucose metabolism
MOTSc: Mitochondrial peptide that enhances metabolic flexibility
5-Amino 1MQ: Reduces visceral fat by modulating NNMT activity
Tirzepatide: GLP-1/GIP agonist for advanced support in metabolic dysfunction
These tools are most effective when used under the guidance of a trained functional practitioner.
Get Ahead of Insulin Resistance Before It Gets Ahead of You
When it comes to your health, one-size-fits-all doesn't work. Comprehensive lab testing and a personalized plan can reveal early signs of insulin resistance and help you take proactive steps. Whether you're already experiencing symptoms or simply want to prevent future disease, improving insulin sensitivity can:
Reduce your risk of chronic illness
Boost your energy and mood
Enhance hormone balance and body composition
Support longevity and daily vitality
Your future health starts with the steps you take today.
If you're experiencing signs of insulin resistance—or simply want to optimize your energy, hormones, and longevity—I'd love to support you. Together, we can create a personalized plan rooted in functional medicine to help you feel your best from the inside out. Schedule a consultation with me.
REFERENCES
(1) Tufts University, 2022 – Only 7% of American Adults Have Good Cardiometabolic Health
Res
Restorative Wellness Solutions Blood Sugar Regulation Module, August 24, 2022
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