New Study Reveals Fasted Cardio May Spike Blood Sugar & Disrupt Metabolism

A 2024 study in Clinical Nutrition ESPEN found that performing cardio in a fasted state triggered a sharp post-exercise insulin spike and elevated blood glucose. ~ While fasted training has gained popularity for fat-burning, the rebound in insulin sensitivity can strain the body's metabolic regulation and actually impair long-term fat oxidation.
This hormonal response becomes even riskier for athletes or active individuals who already have high energy demands. Fasted training without strategy = stress on the system.

Conclusion: Fasted cardio may feel effective short term, but the science shows it can compromise long-term metabolic health.

Fuel smart, not empty. 

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