Research Impact: Current literature has investigated the nutritional regulation of acute and chronic exercise-induced metabolic adaptations in muscle following endurance exercise, principally comparing the impact of training in fasted and carbohydrate-fed (CHO) conditions. Alternative strategies such as exercising in low CHO, protein-fed conditions remain poorly characterized, specifically pertaining to adaptations associated with SIT. Thus, this study aimed to compare the metabolic and performance adaptations to acute and short-term SIT in the fasted state with pre-exercise hydrolyzed (WPH) or concentrated (WPC) whey protein supplementation.
As you would expect, we saw acute differences between feeding conditions in the serum metabolome mainly in AAs and their metabolites, but only minor differences after a period of training. Interestingly, pre exercise protein ingestion attenuated acute exercise-induced increases in muscle pan-acetylation and PARP1 protein content compared with fasted SIT. Previous research has demonstrated a blunting of acute gene expression responses to pre exercise CHO feeding compared with fasted. Pre exercise protein did not blunt the expression of mitochondrial genes measured here, but resulted in similar or favourable outcomes for genes involved in FA transport. Training-induced increases in mitochondrial enzymatic activity (CS & B-HAD) & exercise performance were similar across nutritional groups with some favourable adaptations in the WPH group. Therefore, it appears CHO restricted, but pre exercise protein can support adaptations to SIT & speculatively may have other benefits such as offsetting low energy availability or enhancing post exercise muscle protein synthesis. This research was supported by Carbery Food Ingredients Ltd. and has led to the launch of a new pre exercise product ingredient called Optipep 4power https://www.carbery.com/nutrition/optipep4power/.
Aird, T.P., Farquharson, A.J., Bermingham, K.M., O’Sullivan, A., Drew, J.E. and Carson, B.P., 2021. “Divergent serum metabolomic, skeletal muscle signalling, transcriptomic and performance adaptations to fasted versus whey protein-fed sprint interval training”. American Journal of Physiology-Endocrinology and Metabolism. Vol. 321, No.6. https://journals.physiology.org/doi/full/10.1152/ajpendo.00265.2021