Dietary manipulation for optimizing endurance training adaptations and performance : Carbohydrate vs. fat

The emergence of molecular biology techniques in the sport and exercise sciences has provided researchers with the tools to evaluate the effects of specific training interventions on training adaptation by elucidating many of the cellular and molecular markers that underpin exercise performance. However, while countless studies have sought to determine the optimal intensity, duration, or modality of exercise to induce adaptation, the role of nutrient availability in maximizing these effects has received less attention. Indeed, it has only recently become apparent that changes in nutrient status can alter a number of cell-signalling pathways via nutrient–gene or nutrient–protein interactions. As a result, there has been increased interest in how nutrient availability may promote or inhibit training adaptation and, ultimately, performance capacity. This chapter seeks to address the overlap between nutrition and molecular exercise physiology and to outline some of the existing and emerging theories regarding the optimization of adaptations to endurance training. Topics include manipulation of glycogen content, periodized carbohydrate availability, and consumption of a low-carbohydrate, high-fat diet. We place these dietary strategies in context with an overview of pathways of energy production and the cell-signalling pathways that underpin training adaptation.