Training Science Podcast ZONE 2 SHOWDOWN - with Dr Kristi Storoschuk & Prof Paul Laursen
Aug 8, 2025
Kristi Storoschuk, a PhD candidate whose innovative research challenges traditional views on Zone 2 training and fasting, joins Professor Paul Laursen. They dissect the myths surrounding fasting and the effects of nutrition on athletic performance, emphasizing the differences between human and rodent studies. The duo discusses the significance of mitochondrial health, the potential benefits of low-carb diets for athletes, and the dual challenges faced during an 80K ultra trail run, all while advocating individual experimentation in training and nutrition for optimal results.
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Fasting Rarely Activates AMPK In Human Muscle
- Kristi Storoschuk's systematic review found almost no evidence that fasting activates AMPK in human skeletal muscle.
- Rodent studies are inconsistent, so human benefits cannot be inferred from animal data.
Energy Demand, Not Intake, Drives AMPK
- Kristi argues AMPK responds to energetic demand from increased expenditure, not to reduced intake alone.
- Fasting without raising energy output doesn't create the cellular stress needed to activate AMPK.
Rodents Show Glycogen Loss Not Seen In Humans
- Kristi explains rodents deplete muscle glycogen during fasts, linking to AMP/ADP accumulation and AMPK activation.
- Humans preserve muscle glycogen even after 72-hour fasts, so the rodent mechanism likely doesn't translate.
