65: Insulin Resistance Changes Everythin...

What if insulin resistance is quietly driving inflammation, weight gain, and thyroid dysfunction years before blood sugar ever looks abnormal?

In this episode of Modern Thyroid and Wellness, McCall McPherson sits down with endocrinologist Dr. Alessia Roehnelt for an in-depth discussion on insulin resistance and why it is one of the most important predictors of long-term health outcomes.

Dr. Roehnelt explains how insulin functions in the body, what happens when insulin resistance develops, and why chronically elevated insulin drives inflammation, weight gain, metabolic dysfunction, and disease progression. The conversation highlights the strong bidirectional relationship between insulin resistance and thyroid dysfunction, including how each can worsen the other when left unaddressed.

Together, they explore early warning signs of insulin resistance, optimal lab markers, lifestyle interventions, and when medications like metformin or GLP-1 agonists may be appropriate. This episode emphasizes early detection, individualized care, and the importance of addressing inflammation to restore metabolic health.

🔑 Key Topics Covered

1. What insulin resistance is and how it develops over time
2. How insulin drives inflammation and impacts every organ system
3. Why insulin resistance often precedes prediabetes and type 2 diabetes
4. Common physical signs of insulin resistance, including acanthosis nigricans
5. Rapid weight fluctuations and carb sensitivity as hallmark symptoms
6. The bidirectional relationship between insulin resistance and hypothyroidism
7. How insulin resistance affects thyroid hormone absorption and conversion
8. Why insulin is often a better early marker than hemoglobin A1c
9. Optimal vs. “normal” lab ranges for fasting glucose, insulin, and A1c
10. Why lab reference ranges shift with population health trends
11. The role of vitamin D as both a vitamin and hormone in metabolic health

🧪 Labs & Metrics Discussed

1. Fasting insulin (ideally low with normal glucose)
2. Fasting blood glucose (optimal range below the high 90s)
3. Hemoglobin A1c for long-term glucose trends
4. Liver enzymes (AST, ALT) and their link to fatty liver
5. Thyroid function tests and thyroid antibodies
6. Vitamin D levels and their systemic impact

🏃‍♀️ Lifestyle Strategies for Improving Insulin Sensitivity

1. Prioritizing adequate, consistent sleep to lower cortisol
2. Strength and resistance training...