How to Avoid Insulin Resistance and Why it's Important | Dr. Robert Lustig & Dr. Dom D'Agostino
What this video covers
This April 2023 Levels Health conversation pairs Lustig with Dr. Dominic D’Agostino, a metabolic researcher known for his work on ketogenic physiology — two experts approaching insulin resistance from complementary angles. The format is a structured dialogue rather than a lecture, with the two trading mechanisms, caveats, and disagreements across 77 minutes.
The discussion opens on fundamentals — what insulin is, what insulin resistance means at the cellular level — then moves into Lustig’s claim that there are three distinct types of insulin resistance, each with different drivers and implications. From there the two take on several live controversies: whether weight management is really about “calories in, calories out” (both argue it is not), whether adding more insulin is the right answer for Type 2 diabetes (Lustig argues it is not necessarily), and whether intermittent fasting is necessary (treated as an open question rather than a settled prescription).
A notable thread is insulin as a biomarker: both argue that a high or rising insulin level is itself a problem worth monitoring, and that fasting insulin is an underused test. The conversation also touches on leucine (excess intake of which, Lustig argues, can drive insulin resistance) and closes, characteristically for Lustig, on fiber — which he argues feeds the gut microbiome and is crucial for metabolic health.
Key points
- Lustig and D’Agostino define insulin resistance as cells failing to respond to insulin’s signal to take up glucose, and identify it as the hallmark of prediabetes, Type 2 diabetes, and broader metabolic dysfunction.
- Lustig argues there are three types of insulin resistance, each with distinct mechanisms — a nuance he says is lost when the condition is treated as one thing.
- Both argue weight management is not reducible to “calories in, calories out,” presenting hormonal and metabolic drivers as the decisive variables.
- Lustig argues that adding more insulin is not necessarily the answer for Type 2 diabetes, since hyperinsulinemia is itself part of the pathology in his telling — “the glucose isn’t the problem, the insulin is the problem,” he says, “and the more insulin the quicker you die.”
- He offers the “Little Women of Loja” as his case that calories and weight aren’t the real variable: an Ecuadorian group with Laron dwarfism (defective growth-hormone signaling) who, he says, are very obese yet get “zero diabetes and zero cancer,” while their thin wild-type relatives get both.
- He recounts Jerry Shulman’s turn from muscle to liver: Shulman’s early work used 1.5-Tesla magnets that could only image the gastrocnemius muscle, he says, but once 3-Tesla magnets could image liver fat, the liver proved to matter most — another route to “fix the liver.”
- On insulin-resistance supplements (berberine, alpha-lipoic acid, chromium, turmeric, GOLO and the like): “show me the data,” he says — they work “in the dish,” but he has not seen randomized controlled trial evidence that any of them durably fixes insulin resistance in people.
- They present insulin as a crucial biomarker, arguing a high or rising insulin level is a warning sign that deserves monitoring even before glucose rises.
- Lustig argues excessive leucine intake can lead to insulin resistance — a specific, less-discussed dietary mechanism.
- He closes on fiber as crucial for metabolic health, arguing it feeds the gut microbiome and protects against insulin resistance.
- He says he is for intermittent fasting “for the right patient,” citing a paper suggesting time-restricted eating works in patients with liver fat (a chance for the liver to clear fat) — but not necessarily for everyone.