Why You're Insulin Resistant (And Don't Know It) | Dr. Casey Means
What this video covers
Recorded in 2022, two years before Good Energy, this Ultimate Health Podcast interview with host Jesse Chappus captures Casey Means in her role as co-founder and chief medical officer of Levels, the continuous glucose monitor (CGM) company. She explains why she sees blood sugar as the best available real-time readout of metabolic health, walks through the physiology of glucose spikes and insulin resistance, and shares what Levels members’ data showed about personalized responses to food — down to experiments with oatmeal, rice, and a tablespoon of vinegar.
Key points
- Means argues blood sugar is a proxy for the whole metabolism because food, sleep, movement, stress, the microbiome, environmental toxins, and sunlight all register in it — and that keeping glucose stable and low-variability is, in her framing, a foundation for longevity and chronic disease prevention.
- She lists five harms of repeated glucose spikes: inflammation, oxidative stress, glycation (she gives sugar binding to collagen as part of why skin wrinkles), reactive hypoglycemia — the post-meal crash that drives fatigue, anxiety, and cravings — and ultimately insulin resistance.
- Means explains insulin resistance as cells down-regulating their insulin receptors when overwhelmed, forcing the pancreas to secrete ever more insulin (hyperinsulinemia); she links insulin resistance to nine of the ten leading causes of death in the U.S. and notes 74% of American adults are overweight or obese.
- Citing a Weizmann Institute study published in Cell, in which roughly 800 volunteers ate standardized meals wearing CGMs, Means says people spiked wildly differently on identical food, with gut microbiome composition among the biggest predictors — her core argument for personalized nutrition over generic diet rules.
- From her own CGM data, Means says oatmeal spikes her glucose 70–80 points and sweet potatoes spike her too, so she swaps in chia pudding, cauliflower rice, and cook-cool-reheat rice (which she says creates resistant starch), while eating 95–100% plant-based.
- She describes a Levels member challenge in which about 100 people drank an ounce of vinegar before carb-heavy meals: the vinegar group spent 31 minutes above the 70–110 mg/dL target range versus 43 minutes without, with an average glucose rise of 24.3 versus 31.4 mg/dL — and a much larger gap before pizza (22 versus 36.5). Means is explicit that this is uncontrolled, real-world member data, not a clinical trial.
- Means tells the story of a Levels member, a former retail CEO, who she says lost nearly 100 pounds in about a year by cutting everything that spiked her glucose, with fasting insulin falling from 30 to 5 — while stressing the story is an anecdote, not proof.
- She closes with six dietary building blocks — foods that don’t spike glucose, micronutrient density, fiber, fermented foods, omega-3s, and organic food (arguing glyphosate can impair mitochondria) — and says she supplements based on functional testing such as Genova’s NutrEval because, she argues, modern soil depletion makes food alone unreliable.