**5. Conclusions and Practical Application**

The availability of endogenous and exogenous CHO, fat, and protein before and during exercise can influence the acute and longer-term responses to endurance exercise. Acutely, CHO ingestion inhibits fat burning, however evidence showing enhanced fat burning capacity following long-term training in the fasted state is lacking. Contrasting findings related to the influence of CHO ingestion on mitochondrial signaling may be related to the amount of carbohydrate consumed and the intensity of exercise. Consumption of >120 g CHO before submaximal, steady-state exercise has blunted mitochondrial signaling, while <70 g CHO has not, ye<sup>t</sup> CHO availability appears to have minimal effects following HIIT exercise. Performance is improved following pre-exercise CHO ingestion for longer but not shorter duration exercise, while training-induced performance changes following various pre-exercise nutrition strategies vary based on the type of nutrition protocol used. Caution should be used when generalizing these findings to wider populations, as the majority of research participants have been trained males between 20–30 years of age. In addition to wider participant demographics, more research is needed on the acute and longer-term e ffects of pre-exercise protein ingestion, studies in endurance-trained subjects performing fasted-state training compared with ingesting moderate and low-CHO meals before exercise, and fasted vs. fed-state training without CHO ingestion during exercise.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/2072-6643/12/11/3472/s1, References for studies included in pooled analyses.

**Author Contributions:** Conceptualization, J.A.R., A.E.K., and D.J.P.; data curation, J.A.R.; writing—original draft preparation, J.A.R.; writing—review and editing, J.A.R., A.E.K., and D.J.P.; visualization, J.A.R. and D.J.P.; supervision, A.E.K. and D.J.P. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Acknowledgments:** The authors thank Tom Stewart for his technical assistance.

**Conflicts of Interest:** The authors declare no conflict of interest.
