Why You Need FAR Less Carbs Than You Think Especially During Exercise & Ketones As An Alternate Fuel
Ben Greenfield LifePublished on February 21, 2026
Summary authored by editor@wellifi.com
TLDR Summary
In a recent podcast, Dr. Andrew Kudnik discusses the role of carbohydrates and ketones in athletic performance, emphasizing that maintaining stable blood glucose levels is more critical than previously thought. He advocates for a lower carbohydrate intake while incorporating exogenous ketones to enhance performance.
Key Points
- Insulin is directed to the liver first, not muscles, after carbohydrate consumption.
- Exogenous ketones can help maintain energy levels, especially for those with type 1 diabetes.
- Research suggests athletes may need fewer carbohydrates than traditionally recommended to sustain performance.
The Critical Role of Carbohydrates in Exercise Performance: Insights from Dr. Andrew Kudnik
In a recent episode of the podcast, Ben Greenfield engages in an enlightening conversation with Dr. Andrew Kudnik, a researcher with a deep understanding of metabolism and nutrition. This episode serves as a follow-up to their previous discussion, diving deeper into the intricacies of carbohydrates, insulin, and the alternative fuel sources available for athletes.
Understanding Insulin and Carbohydrate Consumption
When carbohydrates are consumed, they elevate blood glucose levels, prompting the release of insulin. Interestingly, the first destination of insulin is not the muscles but rather the liver, which plays a crucial role in managing blood glucose levels. This process is significant for athletes, especially those like Dr. Kudnik who have type 1 diabetes, as it directly impacts exercise performance.
The Importance of Ketones
Dr. Kudnik emphasizes that during exercise, particularly in mixed-intensity sports like jiu-jitsu, maintaining stable blood glucose levels is vital. He discusses the benefits of ketones as an alternative fuel source, especially in situations where blood sugar levels might drop too low. Exogenous ketones can provide an additional energy source for both cognitive and physical performance.
Carbohydrates: Less is More?
Contrary to traditional beliefs, Dr. Kudnik points out that athletes may not need as many carbohydrates as previously thought. His recent review of over 600 studies indicates that sustaining blood glucose levels is more important than merely loading up on carbohydrates. In fact, maintaining a level of around 10 grams of carbohydrates per hour during prolonged exercise was shown to be effective.
Key Findings from Recent Research
- The strongest predictor of exercise performance is the sustainment of blood glucose levels, not just carbohydrate storage.
- In a study analyzing carbohydrate intake during exercise, only small amounts (10 grams/hour) were needed to maintain performance.
- High carbohydrate diets can lead to pre-diabetic glucose levels in some athletes, indicating a need to rethink nutritional guidelines.
Practical Implications for Athletes
The implications of this research are significant. Athletes may benefit from reducing carbohydrate intake while focusing on maintaining stable blood glucose levels through smaller, more frequent doses of carbohydrates during exercise. This approach not only supports performance but also mitigates the risk of hypoglycemia.
Integrating Ketones into Training
Dr. Kudnik also discusses various forms of exogenous ketones available on the market, including 1,3-butanediol and beta-hydroxybutyrate. These compounds can enhance brain energy metabolism, making them a valuable addition to an athlete's nutritional regimen.
Conclusion
This engaging conversation with Dr. Kudnik sheds light on the evolving understanding of carbohydrates and their role in athletic performance. As research continues to unravel the complexities of nutrition, athletes are encouraged to consider both their carbohydrate intake and the potential benefits of ketones in their training regimens.
For more insights, check out the full podcast episode on Ben Greenfield Life.