#299 - Do Athletes Really Need More Carbs? | Dr. Andrew Koutnik & Mike Haney
LEVELS – A Whole New LevelShow Notes
Most athletes are told the same basic rule: the harder you train, the more carbs you need. But Dr. Andrew Koutnik argues the science is more complicated.
In this episode, Mike Haney talks with Dr. Koutnik about how the body fuels exercise, why muscle glycogen may not explain “hitting the wall” as neatly as many people think, and why blood glucose, brain energy, insulin, and metabolic flexibility may matter more than conventional sports nutrition advice suggests.
They discuss whether athletes really need 60, 90, or even 120 grams of carbs per hour, why some athletes may perform well on far less, and how to think about fueling as an individual experiment rather than a universal rule. Because apparently even “eat sugar while running” was too simple for human physiology to leave alone.
Free course: Improve your metabolic health Get our free email course on how glucose, nutrition, exercise, sleep, and measurement can help you build habits that support better energy and long-term health: https://levels.link/wnl
🎙️ About the Guest: Dr. Andrew Koutnik is a Visiting Research Scientist at the Florida Institute for Human and Machine Cognition, studying nutrition, metabolism, Type 1 diabetes, and human performance. He earned his PhD in medical sciences from the University of South Florida and has worked with groups including NASA and the Department of Defense.
📍What Dr. Andrew Koutnik & Mike Haney discussed: 00:42 Why carbs became central to sports nutrition 05:30 How the body uses carbs, fat, ketones, and lactate for fuel 13:45 Exercise, insulin sensitivity, and blood glucose 21:20 Why muscle glycogen may not explain performance limits 31:00 What “hitting the wall” may really mean 39:15 The case for lower-carb fueling strategies 48:30 Why more carbs don’t always mean better performance 58:00 The problem with 90–120 grams of carbs per hour 1:08:30 How athletes can test fueling for themselves 1:17:00 What this means for everyday exercisers and marathoners
🔗 Helpful Links:Watch the conversation: https://youtu.be/FfomxfyCchw Study discussed: Carbohydrate Ingestion on Exercise Metabolism and Physical Performancehttps://academic.oup.com/edrv/article/47/2/191/8432248Related paper: Substrate Oxidation Does Not Influence Middle Distance Running Performancehttps://www.mdpi.com/2072-6643/17/17/2771 Find us on YouTube: https://youtube.com/levelshealth?sub_confirmation=1
📲 Connect:Connect with Dr. Andrew Koutnik: https://andrewkoutnik.com/X: https://x.com/AKoutnikInstagram: https://www.instagram.com/andrewkoutnikphd/Google Scholar: https://scholar.google.com/citations?hl=en&user=2BzUjqkAAAAJ
👋 Who we are: Levels helps you understand your metabolic health with personalized data, expert guidance, and tools that connect your daily choices to measurable changes in your body. Our goal is to help you make better decisions about food, exercise, sleep, and long-term health.
More from LEVELS – A Whole New Level
Heart disease is the leading cause of death, but it’s also one of the most preventable. Decades of research have established a strong causal role for LDL and other ApoB-containing particles in atherosclerosis, and we now have multiple proven ways to lower them. The harder question is how to turn that evidence into a decision for an individual person. Mike Haney talks with Johns Hopkins cardiologist Dr. Seth Martin, a co-author of the new 2026 dyslipidemia guidelines, about what the latest evidence says we should actually measure and act on. The throughline is pragmatic: lower exposure to atherogenic particles earlier and for longer, use additional tests when they can change a decision, and distinguish interesting new measurements from ones that have actually been shown to improve outcomes.
Most of NextLevel starts with a measurement problem: we can see more biology than ever, but we still have to figure out what to do with it. Bioelectronic medicine flips that sequence. We already know how to send electrical signals into the nervous system to change biology, including an FDA-approved vagus nerve treatment for rheumatoid arthritis, even though we still can’t map or read most of the individual nerve fibers carrying those signals.
Most health decisions happen before the science is settled. A study points one way, another points somewhere else, experts disagree about what matters, and even strong population-level evidence may not tell you what will happen to you.
Most medical imaging happens after a symptom, injury, or abnormal test gives a clinician a reason to look. But what changes if imaging becomes a more routine measurement, creating a record of the body before something goes wrong? In this episode of Next Level, Mike Haney talks with Dr. Daniel Durand, chief medical officer at Prenuvo, about whole-body MRI as a test case for a broader shift from episodic medicine toward longitudinal health data. Whole-body MRI is controversial, and Durand is clearly an advocate. The conversation takes the skepticism seriously, then asks a larger question: as measurement gets cheaper, more frequent, and increasingly visible to patients themselves, how should medicine decide what is worth knowing?
Alcohol has spent the last 40 years bouncing between two health narratives: a little is good for your heart, or any amount is dangerous. The science doesn’t really support either slogan. Dr. Tim Naimi has spent decades studying the health effects of alcohol and, just as importantly, why the research is so difficult to interpret. His read of the evidence is less dramatic but more useful: there’s no good reason to start drinking for your health, very low intake may carry little measurable added risk, and risk rises as consumption does. Understanding why earlier studies made moderate drinking look protective helps explain a lot of the whiplashing headlines.