Substrate oxidation may not affect middle distance running performance 🔥
High carb or high fat, you choose!
Substrate Oxidation Does Not Influence Middle Distance Running Performance: A Randomized Controlled Crossover Trial
Study Details
This new study recruited 30 recreational distance runners who were assigned to complete either a…
⏱️ 5k time-trial (n = 15)
⏱️ 10k time-trial (n = 15)
Runners in each group also consumed one of two isocaloric (~1000 kcal) pre-exercise meals…
🥑 low-carbohydrate high-fat (LCHF)
🍞 high-carbohydrate low-fat (HCLF)
Dietary intake, activity, and body weight were controlled for prior to and during the interventions 🔍
Here is what they found ⬇️
Key Findings
The LCHF meal led to a…
📈 77% higher rate of fat oxidation
🔥 5% lower RER
…with corresponding reductions in carb oxidation 📉
However, there were no significant differences in time-trial performance (5k or 10k) between meals 🍽️
Regarding blood parameters…
🩸 Capillary R-βHB increased modestly after LCHF
🩸 Blood glucose increased after HCLF only
The LCHF meal also was 35% more filling than the HCLF meal 😮💨
Conclusion
Pre-exercise meal composition and subsequent substrate oxidation do not appear to affect middle distance running performance ✅
Would this be similar for longer distance events? That remains TBC 🧐
Reference
https://www.mdpi.com/2072-6643/17/17/2771
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