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#337 - Insulin resistance masterclass: The full body impact of metabolic dysfunction and prevention, diagnosis, and treatment | Ralph DeFronzo, M.D.

Feb 24, 2025 2h 26m 27 insights
<p><a href="https://peterattiamd.com/ralphdefronzo/?utm_source=podcast-feed&amp;utm_medium=referral&amp;utm_campaign=250224-pod-ralphdefronzo&amp;utm_content=250224-pod-ralphdefronzo-podfeed"> View the Show Notes Page for This Episode</a></p> <p><a href="https://peterattiamd.com/subscribe/?utm_source=podcast-feed&amp;utm_medium=referral&amp;utm_campaign=250224-pod-ralphdefronzo&amp;utm_content=250224-pod-ralphdefronzo-podfeed"> Become a Member to Receive Exclusive Content</a></p> <p><a href="https://peterattiamd.com/newsletter/?utm_source=podcast-feed&amp;utm_medium=referral&amp;utm_campaign=250224-pod-ralphdefronzo&amp;utm_content=250224-pod-ralphdefronzo-podfeed"> Sign Up to Receive Peter's Weekly Newsletter</a></p> <p>Ralph DeFronzo is a distinguished diabetes researcher and clinician whose groundbreaking work on insulin resistance has reshaped the understanding and treatment of type 2 diabetes. In this episode, Ralph shares insights from his five decades of research, including his pivotal role in bringing metformin to the U.S. and developing SGLT2 inhibitors. Ralph explores the impacts of insulin resistance on specific organs, the pharmacologic interventions available, and the gold-standard euglycemic clamp method for measuring insulin resistance. This episode is a masterclass in the pathophysiology and treatment of type 2 diabetes, featuring an in-depth discussion of GLP-1 receptor agonists, metformin, and a lesser-known class of drugs that opened Peter's eyes to new possibilities in diabetes care.</p> <p><strong>We discuss:</strong></p> <ul type="disc"> <li>Metabolic disease as a foundational driver of chronic illness [4:00];</li> <li>Defining insulin resistance: effects on glucose, fat, and protein metabolism, and how it varies between healthy, obese, and diabetic individuals [8:15];</li> <li>The historical significance of the development of the euglycemic clamp technique for measuring insulin resistance [11:45];</li> <li>How insulin affects different tissues: liver, muscle, and fat cells [15:00];</li> <li>The different ways insulin resistance manifests in various tissues: Alzheimer's disease, cardiovascular disease, and more [25:00];</li> <li>The dangers of hyperinsulinemia, and the importance of keeping insulin levels within a physiological range [29:00];</li> <li>The challenges of identifying the genetic basis of insulin resistance and type 2 diabetes [37:00];</li> <li>The "ominous octet"—a more comprehensive model of type 2 diabetes than the traditional triumvirate [45:45];</li> <li>The kidneys' unexpected role in worsening diabetes, and how SGLT2 inhibitors were developed to treat diabetes [55:45];</li> <li>How insulin resistance in the brain and neurocircuitry dysfunction contribute to overeating and metabolic disease [1:04:15];</li> <li>Lipotoxicity: how overeating fuels insulin resistance and mitochondrial dysfunction [1:07:30];</li> <li>Pioglitazone: an underappreciated and misunderstood treatment for insulin resistance [1:10:15];</li> <li>Metformin: debunking the misconception that it is an insulin sensitizer and explaining its true mechanism of action [1:19:15];</li> <li>Treating diabetes with triple therapy vs. the ADA approach: a better path for diabetes management [1:24:00];</li> <li>GLP-1 agonists, the Qatar study, and rethinking diabetes treatment [1:31:30];</li> <li>Using a hyperglycemic clamp to look for genes that cause diabetes [1:45:15];</li> <li>The superiority of measuring C-peptide instead of insulin to assess beta-cell function [1:46:45];</li> <li>How GLP-1-induced weight loss affects muscle mass, the benefits and risks of myostatin inhibitors, and the need for better methods of evaluating functional outcomes of increased muscle mass [1:51:30];</li> <li>The growing crisis of childhood obesity and challenges in treating it [2:02:15];</li> <li>The environmental and neurological factors driving the obesity epidemic [2:07:30];</li> <li>The role of genetics, insulin signaling defects, and lipotoxicity in insulin resistance and diabetes treatment challenges [2:11:00];</li> <li>The oral glucose tolerance test (OGTT): detecting early insulin resistance and beta cell dysfunction [2:18:30]; and</li> <li>More.</li> </ul> <p>Connect With Peter on <a href="https://twitter.com/PeterAttiaMD">Twitter</a>, <a href="https://www.instagram.com/peterattiamd/">Instagram</a>, <a href="https://www.facebook.com/peterattiamd/">Facebook</a> and <a href="https://www.youtube.com/channel/UC8kGsMa0LygSX9nkBcBH1Sg">YouTube</a></p>
Actionable Insights

1. Precision Diabetes Care

Physicians should adopt a precision medicine approach to type 2 diabetes by identifying the specific phenotype of each patient, rather than treating it as a single, uniform disease, to provide optimal care.

2. Start Combination Therapy Early

Consider starting combination therapy for type 2 diabetes from the outset, as recommended by the American Diabetes Association, rather than a stepwise approach, to address the multiple underlying pathophysiological defects.

3. Optimal Diabetes Drug Regimen

For optimal type 2 diabetes treatment, if cost is not a barrier, prioritize a newer GLP-1 agonist as a foundational drug, add pioglitazone for insulin sensitization, and an SGLT2 inhibitor as a third, especially if there is renal or cardiac disease.

4. Cost-Effective Diabetes Therapy

For effective type 2 diabetes management, consider a triple therapy approach using older, affordable drugs like metformin, exenatide (an older GLP-1 agonist), and pioglitazone, as this combination has shown significant improvements in A1C, insulin sensitivity, and beta cell function.

5. Utilize Pioglitazone (Actos)

Consider pioglitazone (Actos) as a true insulin sensitizer to correct insulin signaling defects and redistribute fat from organs like muscle, liver, and beta cells to subcutaneous tissue, improving overall metabolic health.

6. SGLT2 for Primary Prevention

Consider using SGLT2 inhibitors in newly diagnosed diabetics without existing cardiac symptoms for primary prevention of cardiovascular and renal disease, based on their documented benefits in secondary prevention.

7. GLP-1s Boost Beta Cells

Recognize that GLP-1 agonists are powerful for improving and preserving beta cell function in type 2 diabetes, not just for weight loss, and this effect is crucial for long-term disease management.

8. Reduce Insulin Dosage Physiologically

If you have type 2 diabetes and are taking high doses of insulin (e.g., 75 units/day), aim to reduce it to a more physiological level (around 35 units/day) through nutrition, exercise, and other pharmacological interventions.

9. Avoid Chronic Hyperinsulinemia

Avoid chronic hyperinsulinemia, as it can down-regulate the insulin signaling system and induce insulin resistance, making the condition worse.

10. Implement Lifestyle Changes

Implement lifestyle changes such as weight loss and exercise, alongside appropriate medications (insulin sensitizers or weight-loss drugs), to effectively reduce insulin dosage in individuals with type 2 diabetes.

11. Address Childhood Obesity

Recognize childhood obesity as a critical public health concern leading to early-onset, aggressive type 2 diabetes that is often resistant to conventional treatments, necessitating early and aggressive intervention strategies.

12. Tackle Obesity’s Root Causes

Address the obesity epidemic by tackling multiple contributing factors, including processed and calorically dense foods, lack of exercise, and the resulting changes in brain neurocircuitry related to food intake.

13. OGTT: One-Hour Glucose Predictor

Pay close attention to the one-hour glucose level during an Oral Glucose Tolerance Test (OGTT); a reading greater than 155 mg/dL is a strong predictor of developing type 2 diabetes, regardless of other metrics.

14. OGTT: Hypoglycemia Indicates Resistance

If an OGTT shows a high insulin response at 30 minutes followed by hypoglycemia at two hours, it indicates a pre-diabetic state with significant insulin resistance and an overshooting beta cell response.

15. OGTT: Delayed Insulin Response

A low insulin response at 30 minutes during an OGTT, indicating a loss of first-phase insulin secretion, is a predictor of a primary beta cell defect and future type 2 diabetes development.

16. Measure C-Peptide, Not Insulin

To accurately assess insulin secretion, measure C-peptide levels rather than insulin levels, as C-peptide is not taken up by the liver and thus provides a more reliable measure of pancreatic beta cell output.

17. Understand Tissue-Specific Resistance

When discussing or assessing insulin resistance, specify the affected tissue (e.g., muscle, liver, fat cell, brain) and the particular metabolic process, as insulin’s actions vary across tissues.

18. Embrace Pioglitazone Weight Gain

Do not be deterred by weight gain when using pioglitazone, as studies show that greater weight gain with this drug correlates with improved A1C, insulin sensitivity, beta cell function, blood pressure, triglycerides, and HDL cholesterol due to fat redistribution.

19. Pioglitazone for NASH

Consider pioglitazone (Actos) as the best drug for treating Non-Alcoholic Steatohepatitis (NASH) due to its fat redistribution effects.

20. Pioglitazone Cardiovascular Benefit

Recognize that pioglitazone has demonstrated cardiovascular safety and benefit, with weight gain on the drug paradoxically correlating with reduced mortality in the PROactive study.

21. Metformin: Cost-Effective Addition

Utilize metformin as a cost-effective foundational drug in combination therapy for type 2 diabetes, as it is inexpensive and can be safely added to other medications.

22. Metformin Not Muscle Sensitizer

Understand that metformin primarily reduces hepatic glucose output by inhibiting gluconeogenesis and does not directly improve insulin sensitivity in muscle, as it cannot enter muscle cells.

23. GLP-1 Adherence is Key

When prescribing powerful new drugs like GLP-1 agonists for severe type 2 diabetes, ensure patient adherence, affordability, and proper medical guidance, as these factors are critical for sustained success and preventing relapse.

24. Re-Listen to This Podcast

Listen to this podcast episode with Dr. Ralph DeFranzo multiple times to fully grasp the complex information on type 2 diabetes and insulin resistance.

25. Listen to Shulman Episode

Listen to Peter Attia’s previous podcast episode with Jerry Shulman to understand insulin resistance, particularly its manifestation in muscle.

26. Sophisticated Beta Cell Testing

For precise assessment of beta cell function in a research or specialized clinical setting, consider advanced techniques like a three-step hyperglycemic clamp followed by sequential infusions of GLP-1 and amino acids to measure specific responses to different stimuli.

27. Support Peter Attia’s Content

Become a premium member of Peter Attia’s podcast/website for advanced health and wellness knowledge and exclusive content, as it’s designed to provide value exceeding the subscription cost.