Macro partitioning
Consuming low glycemic index (LGI) meals prior to high-intensity exercise does not increase fat oxidation and instead increases carbohydrate oxidation compared to high glycemic index (HGI) meals.
If you are eating before intense exercise, do not assume that 'low glycemic' or 'stable blood sugar' meals will help you burn more fat. This study shows that LGI meals actually increased carbohydrate burning and decreased fat burning compared to high glycemic meals. Focus on total carbohydrate availability and timing rather than just the glycemic index if your goal is optimizing substrate oxidation for high-intensity efforts.
LGI meals resulted in lower fat oxidation and higher carbohydrate oxidation than the HGI meal in the postprandial period.
Why this rating
Controlled crossover clinical trial with rigorous metabolic measurements (indirect calorimetry) in trained athletes.
Source
Metabolic responses to high glycemic index and low glycemic index meals: a controlled crossover clinical trial
Paula Guedes Cocate et al. · Nutrition Journal · 2011
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