Research

Mixed

Consuming carbohydrates before and during exercise blunts the molecular signaling pathways (AMPK, p38MAPK) that are normally enhanced by low carbohydrate availability.

If your goal is to improve your body's metabolic efficiency (mitochondria and fat burning), avoid eating carbohydrates before and during your training session. Eating carbs will blunt the specific cellular signals (AMPK, p38MAPK) that drive these adaptations. If you need to maintain intensity, try caffeine or mouth-rinsing instead of ingesting carbs.

GoodRefutesHIGH confidence
consuming pre-exercise meals rich in CHO and/or CHO during exercise can down-regulate lipolysis (thereby negating FFA-mediated signalling) as well as reduce both AMPK and p38MAPK activity, thus having negative implications for downstream regulators.
Jonathan D. Bartlett et al. · European Journal of Sport Science · 2014

Why this rating

Supported by multiple studies cited (Civitarese, Akerstrom, Morton).

Source

Carbohydrate availability and exercise training adaptation: Too much of a good thing?

Jonathan D. Bartlett et al. · European Journal of Sport Science · 2014

DOI 10.1080/17461391.2014.920926

narrative_reviewCited 225×
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DOI resolved against Crossref · corpus check 2026-06-10

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