HoldsUp

Andrew Koutnik

Andrew Koutnik is a researcher in the fields of nutrition, exercise physiology, and metabolism. His published research focuses on the effects of carbohydrate intake, exogenous ketone supplementation, and ketogenic diets on exercise performance, metabolism, and cognitive function. Additionally, his work investigates the physiological and cardiovascular impacts of nutritional interventions in individuals with type 1 diabetes.

42 claims checked on air: 5 context 1 contradicted 2 overstated 25 supported 9 unverified

What they said on air - contradicted

4 citing their own research

1:08:19contradictedhighThe Fuel Myth: Rethinking Carbs, Brain Health, and Human Per

Consuming 120 grams of carbohydrates per hour during prolonged strenuous exercise suppresses fat metabolism to approximately 10% of total energy expenditure and shifts over 85% of fuel utilization to glucose, primarily from muscle glycogen.

"when they compare 120 g of carbohydrates per hour compared to just 25 g per hour, one at 120 g per hour, insulin was infinitely higher, okay? But you essentially blocked fat metabolism to around 10% of total energy substrate used during a prolonged strenuous form of exercise. And you expedited muscle glycogen breakdown. Over 85% of the fuel came from glucose and most of it from muscle glycogen." (said at 1:08:19)

The claim asserts that ingesting 120 g/h of carbohydrates during prolonged strenuous exercise "expedited muscle glycogen breakdown" and that "most of it [came] from muscle glycogen." In exercise physiology and tracer studies, exogenous carbohydrate ingestion does not expedite (accelerate) muscle glycogen breakdown; rather, exogenous carbohydrate increases exogenous carbohydrate oxidation and either spares endogenous glycogen stores (particularly liver glycogen and muscle glycogen) or leaves endogenous carbohydrate oxidation unchanged compared to lower doses. Isotope tracer studies evaluating 90–120 g/h carbohydrate ingestion demonstrate that high exogenous carbohydrate intake delivers substantial circulating fuel (exogenous oxidation reaching ~1.5–1.7 g/min), reducing reliance on endogenous stores rather than accelerating glycogen depletion.

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